bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost‐Identification Analysis in Oral Cavity Cancer Management
Authors: Funk Gerry F. , Hoffman Henry T. , Karnell Lucy Hynds , Ricks Joan M. , Zimmerman M. Bridget , Corbae Dean P. , Hussey David H. , McCulloch Timothy M. , Graham Scott M. , Dawson Cindy J. , Means Mary E. , Colwill Margaret L. , Titler Marita G. , Smith Elaine M.
Published: June 2006

The objectives of this study were to investigate potential relationships between pretreatment patient‐mix characteristics, treatment modalities, and costs generated during the pretreatment work‐up, treatment, and 1‐year follow‐up periods for patients with oral cavity cancer (OCC). Another objective was to identify potential areas for cost reduction and improved resource allocation in the management of OCC patients. Using a retrospective cohort of 73 patients with OCC, pretreatment patient‐mix characteristics and treatment modalities were evaluated in relation to university‐based charges incurred during the pretreatment evaluation, treatment, and 1 ‐year follow‐up periods. Simple regression and stepwise multiple regression analyses were used to develop predictive models for cost based on independent variables, including age, AJCC TNM clinical stage, smoking history, American Society of Anesthesiologists (ASA) class, comorbidity as defined by the Kaplan‐Feinstein grade and treatment modality. The dependent measurements included all physician, office, and hospital charges incurred at the University of Iowa Hospitals and Clinics during the pretreatment evaluation, treatment, and follow‐up periods, as well as the total pretreatment through 1‐year follow‐up management costs. Independent variables that were identified as being significantly associated with treatment costs included T classification, N classification, TNM stage, unimodality versus multimodality treatment, and the Kaplan‐Feinstein comorbidity grade. Age, smoking status, and ASA class were not significantly associated with costs. The majority of the OCC management costs were incurred during the treatment period. The most substantial decreases in management costs for OCC will be realized through measures that allow identification and treatment of disease at an early stage, in which single‐modality treatment may effectively be used. Resource allocation for OCC should support the investigation of measures through which the diagnosis and treatment of OCC at the earliest possible stage is facilitated. The presence of comorbid illness is a significant component in the determination of management costs for OCC and should be included in analyses of resource allocation for OCC. The singular diagnosis of OCC encompasses a wide range of patient illness severity, and diagnosis‐related reimbursement schemes for OCC treatment should optimally differentiate between early and advanced stage disease.
Design for an Inexpensive but Effective Cochlear Implant
Authors: Wilson Blake S. , Rebscher Stephen , Zeng Fan‐Gang , Shannon Robert V. , Loeb Gerald E. , Lawson Dewey T. , Zerbi Mariangeli
Published: June 2006

Widespread application of cochlear implants is limited by cost, especially in developing countries. In this article we present a design for a low‐cost but effective cochlear implant system. The system includes a speech processor, four pairs of transmitting and receiving coils, and an electrode array with four monopolar electrodes. All implanted components are passive, reducing to a minimum the complexity of manufacture and allowing high reliability. A four‐channel continuous interleaved sampling strategy is used for the speech processor. The processor and transmission link have been evaluated in tests with a subject previously implanted with the Ineraid electrode array and percutaneous connector. A prototype of the link, consisting of four pairs of transmitting and external receiving coils, was used, with the outputs of the receiving coils directed to four intracochlear electrodes through the percutaneous connector. The subject achieved speech reception scores with the prototype system that were equivalent to those achieved with a standard laboratory implementation of a continuous interleaved sampling processor with current‐controlled stimuli.
Titration Streptomycin Therapy in Meniere's Disease: Long‐Term Results
Authors: Balyan Fatih R. , Taibah Abdelkader , Donato Giuseppe de , Aslan Asim , Falcioni Maurizio , Russo Alessandra , Sanna Mario
Published: June 2006

As soon as the use of streptomycin was started for the treatment of tuberculosis, its ototoxic effect was discovered. Initial reports demonstrated that streptomycin was successful in reducing vestibular responses while preserving cochlear activity. Streptomycin sulfate has been used for almost half a century for the treatment of vertigo in patients with Meniere's disease. At the Gruppo Otologico, Piacenza, Italy, between 1987 and 1995 we treated 16 patients with either bilateral Meniere's disease or with Meniere's disease in their only hearing ear, adopting the titration streptomycin therapy protocol of Graham et al. Three patients with follow‐up periods of less than 2 years were not included in this study. The ages of the patients ranged from 36 to 64 years with a mean of 49.2 years. The patients were observed for 2 to 8.8 years. The dose of administered streptomycin varied from 14 to 49 gm. Episodic vertigo was totally relieved in all of the patients after initial treatment, whereas hearing remained the same or was improved when compared with the pretreatment levels. Five of the patients experienced recurring vertigo during a period of 4 to 24 months after initial treatment. Oscillopsia persisted in two patients and ataxia in darkness persisted in another two patients. Hearing was unchanged in 14 ears, improved in 2 ears, and worsened in 4 ears at the last follow‐up evaluation. The overall outcome indicated that intramuscular titration streptomycin therapy seems to be one of the most important therapeutic options in the treatment of disabling vertigo in patients with either bilateral Meniere's disease or Meniere's disease in an only hearing ear.
Rotifers in saltwater environments, re-evaluation of an inconspicuous taxon
Authors: Fontaneto Diego , De Smet Willem H. , Ricci Claudia
Published: June 2006

Rotifers are microscopic aquatic animals that comprise more than 1800 species. Most rotifer species live in freshwater and limno-terrestrial habitats, while thalassic environments (brackish+seawater) are thought to host few species. No recent review of saline rotifers is available. Here we report the results of a review of the literature concerning rotifers from saline environments, distinguished into three categories: stenohaline, euryhaline, and haloxenous, and found both in truly marine habitats and/or in inland saline waters. A total of about 200 studies, mentioning fully identified rotifers from saline waters, allowed us to list as many as 443 rotifer taxa at either specific, subspecific and infrasubspecific rank, corresponding to 391 nominal species. Truly thalassic taxa, not found in inland saline waters only, accounted for 289, including the ‘stenohaline’ (143) and the euryhaline (146) ones. As for freshwaters, the majority of the thalassic rotifers inhabit the psammon, or display a benthic–periphytic way of life, while the plankton likewise is less species rich and less abundant. The geographical distribution of the brackish and marine rotifers largely reflects the distribution of rotifer investigators, therefore, no biogeographical analysis can be performed yet. In conclusion, the analysis of literature citing rotifers in salt waters, uncovers an unexpected rotifer fauna: the apparent richness of the group in thalassic environments is worthy of being addressed by further investigations, as many species have been reported only by their description, suggesting either considerable endemism or taxonomic errors.
European hydromedusa Eleutheria dichotoma (Cnidaria: Hydrozoa: Anthomedusae) found at high densities in New South Wales, Australia: distribution, biology and habitat
Authors: Fraser Ceridwen , Capa María , Schuchert Peter
Published: June 2006

Eleutheria dichotoma, a hydrozoan not previously recorded from the southern hemisphere, was found at high densities at several locations along the coast of New South Wales (NSW), Australia, between August and November 2005. The identity of the species was confirmed by morphological and molecular (16S rDNA) comparisons with European specimens. Local densities, distribution and habitat (algal substrate) were examined. The medusae were found along a 400 km stretch of coastline between Bateau Bay (33°23′S 151°29′E) and Pebbly Beach (35°35′S 150°43′E), primarily on the green alga Ulva, at mean densities of more than 50 individuals per 10 cm2 plot. The species is probably a recent introduction to Australia.
The cnidome of Carybdea marsupialis (Cnidaria: Cubomedusae) from the Adriatic Sea
Authors: Di Camillo C. , Bo M. , Puce S. , Tazioli S. , Bavestrello G.
Published: June 2006

Kinds and distribution of nematocysts of the cubomedusa Carybdea marsupialis were described by light and scanning electron microscopy. Three kinds of nematocysts were found in tentacles: heterotrichous microbasic euryteles, flattened holotrichous isorhizas and subspherical holotrichous isorhizas. The microbasic euryteles of the tentacles show a characteristic detachable multilayered lancet, already described in the euryteles of Carybdea alata. A possible explanation of the function of the lancet is proposed. The pedalia and the umbrella are armoured by holotrichous isorhizas together with an unidentified kind of small, drop-shaped nematocysts. Gastric cirri, characterized by a rough and ciliated surface, contain heterotrichous microbasic euryteles.
Population and reproductive biology of the fiddler crab Uca chlorophthalmus (Brachyura: Ocypodidae) from Inhaca Island, southern Mozambique
Authors: Litulo Carlos
Published: June 2006

This study aimed to assess the population biology and reproduction of the fiddler crab Uca chlorophthalmus at its limit of geographical distribution, Saco da Inhaca mangrove, southern Mozambique. Monthly samples were conducted at low tide periods between January and December 2003. The size distributions showed uni- and bimodal patterns, with males reaching larger sizes than ovigerous and non-ovigerous females. Females were slightly more abundant than males, but the overall sex ratio (1:1.01) did not differ significantly from 1:1. Uca chlorophthalmus displays continuous reproductive patterns with peaks of breeding in March and December. Moreover, linear correlations revealed that breeding in this crab is controlled by both temperature and rainfall. Similarly, juvenile recruitment was constant, but was more intense in winter (May–July). Brood size was positively associated with female size. Timing of the observed breeding pattern in the study area may enhance reproductive output and recruitment of the species.
Small-scale spatial changes in estuarine fish: subtidal assemblages in tropical Brazil
Authors: Chagas L.P. , Joyeux J.-C. , Fonseca F.R.
Published: June 2006

Monthly sampling was conducted during one year in three zones along the estuarine gradient of Baía de Vitória, Brazil. Within each zone, unreplicated night trawls were done in deep subtidal flats located 130–210 m away and 2–3 m deeper than shallow ones. Twenty-one taxa represented 97.5% of the total mean fish abundance. The taxa Achirus lineatus (mean±SD: 2076±1269 10−4 m2), Eucinostomus spp. (694±807), Symphurus tessellatus (400±626), Sphoeroides testudineus (367±597) and Lutjanus synagris (323±445) dominated the deep assemblage (N=36) while Eucinostomus spp. (3649±4913), A. lineatus (1287±1569), S. testudineus (1208±1986), L. synagris (1101±927) and Sphoeroides greeleyi (569±1404) dominated the shallow assemblage (N=35). Taxa exclusive of one or the other depth showed extremely low abundance. The low-salinity shallow flats showed higher total abundance and taxa number than the high salinity deep locales but richness, diversity and equitability showed no significant differences among the six stations. The assemblage structure was significantly correlated to the depth structure but not to physico-chemical characteristics of the water. However, the spatial distribution of individual species varied greatly, from depth-dependent pattern to estuarine gradient-dependent pattern, with several intermediates. The community structure is singular in comparison to that of other tropical Brazilian estuaries studied to date. This is probably related to its geographical position in a transitional zone between the northern, tropical Brazilian oceanic domain and the southern, subtropical-temperate domain.
Food and feeding ecology of the striped dolphin, Stenella coeruleoalba, in the oceanic waters of the north-east Atlantic
Authors: Ringelstein Julien , Pusineri Claire , Hassani Sami , Meynier Laureline , Nicolas Rémi , Ridoux Vincent
Published: June 2006

The food and feeding ecology of the striped dolphin, Stenella coeruleoalba, in the oceanic waters of the north-east Atlantic were studied using the stomach contents of 60 striped dolphins caught in the albacore drift-net fishery throughout the summer months of 1992 and 1993 off the Bay of Biscay. Thirty-eight per cent of these dolphins were calves (0–1 years old), 25% were juveniles (2–8) and 37% were mature adults (9–32, of which 7 females and 14 males). The diet was found to be primarily composed of fish (39% by mass (M)) and cephalopods (56% M) and secondarily of crustaceans (5% M). The most significant fish family identified was the lanternfish (24% M) with Notoscopelus kroeyeri and Lobianchia gemellarii being predominant. Among squid, the oceanic Teuthowenia megalops and Histioteuthis spp. were the most significant. The pelagic shrimp Sergastes arcticus and Pasiphaea multidentata were the most prevalent crustaceans. Prey sizes ranging from 30 to 170 mm accounted for 80% of the prey items while 80% of the reconstituted biomass consisted of prey measuring between 60 and 270 mm. Prey composition and size-range differed slightly with sex and age or body size of the dolphins. The state of digestion of food remains suggested that predation took place at dusk or during the early hours of the night on which the dolphins were caught.
Le fonctionnement du pronom adverbial y et la concurrence entre y, là et là-bas en emploi spatial
Authors: LORENTZEN LISE RICHTER
Published: June 2006

En dépit de leur nature et de leur fonctionnement syntaxique distincts, le pronom y en emploi spatial se trouve en concurrence, sur les plans sémantique et pragmatique, avec les deux adverbes là et là-bas. En termes d'accessibilité cognitive, il sera montré que les référents de y jouissent d'une plus grande accessibilité que ceux des deux adverbes. Les trois marqueurs ont tous des emplois anaphoriques. Si là et là-bas s'emploient également de manière déictique, tel n'est pas le cas pour y. Là-bas est le seul à pouvoir marquer la distance par rapport au locuteur. Quant à la progression thématique, les trois marqueurs peuvent exprimer le thème, mais y n'est jamais rhématique, contrairement aux deux autres. Enfin, y et là-bas sont plus aptes que là à marquer un processus spatial dynamique.
Bubbles generated from wind‐steepened breaking waves: 2. Bubble plumes, bubbles, and wave characteristics
Authors: Leifer Ira , Caulliez Guillemette , de Leeuw Gerrit
Published: June 2006

Measurements of breaking‐wave‐generated bubble plumes were made in fresh (but not clean) water in a large wind‐wave tunnel. To preserve diversity, a classification scheme was developed on the basis of plume dimensions and “optical density,” or the plume's ability to obscure the background. Optically dense plumes were due to the presence of a peak at large radius in the plume bubble size distribution. For each class, the plume formation rate, P, was measured at different fetches. The relationship between wave‐breaking characteristics and the bubble plume evolution is examined in detail for these experiments. The wave‐breaking rate and intensity were strongly fetch‐dependent as the mechanically steepened wind waves rapidly evolved with fetch because of wind, dissipation, and nonlinear wave‐wave interactions. P followed the trend in wave breaking, reaching a maximum at the fetch of maximum wave breaking. The ratio of dense to diffuse plumes was more sensitive to the wave‐breaking intensity. Using P and the bubble population size distributions for each class, the global bubble plume injection size distribution, Ψi(r), where r is radius, was calculated. Ψi decreased as Ψi ∼ r−1.2 for r < 1700 μm and Ψi ∼ r−3.9 for larger r. Total volume injection was 640 cm3 s−1, divided approximately equally between bubbles smaller and larger than 1700‐μm radius. Using plume volumes at maximum penetration for each class, a concentration distribution was calculated and showed plume concentrations greater than the background population by one to several orders of magnitude, depending upon r.
Experimental deformation of synthetic wet jadeite aggregates
Authors: Orzol J. , Stöckhert B. , Trepmann C. A. , Rummel F.
Published: June 2006

Predictions on interplate coupling and shear heating in the deeper levels of subduction zones require an understanding of the rheology of eclogite. The strength of eclogite is probably limited by the flow strength of its major constituent omphacite, representing a solid solution between the clinopyroxene end‐members diopside and jadeite. Here we report the results of deformation experiments on the end‐member jadeite (NaAlSi2O6), carried out on fine‐grained synthetic aggregates crystallized in the stability field of jadeite from a synthetic glass precursor. A standard procedure was established to yield samples with a uniform microstructure and an average grain size of approximately 10 μm. The presence of micropores and the detection of small amounts of freezable water by Fourier transform infrared spectroscopy (FTIR) in both undeformed and deformed samples indicates the presence of a free aqueous fluid, hence wet conditions. Deformation experiments were carried out in a modified Griggs‐type apparatus at a confining pressure of 2.5 GPa, temperatures between 800°C and 1100°C and at strain rates of 4 × 10−4 s−1 to 2 × 10−6 s−1. A molten eutectic CsCl/NaCl mixture was used as pressure medium. The microfabrics of the deformed samples and the mechanical data indicate deformation in the dislocation creep regime. The mechanical data are fit by a power law using a global inversion method, yielding an activation energy of Q = 326 ± 27 kJ mol−1, a stress exponent n = 3.7 ± 0.4, and a preexponential factor of ln A = −3.3 ± 2.0. Extrapolation of this flow law for synthetic jadeitite to low geological strain rates, and comparison with available flow laws for diopside, indicates jadeite to be significantly weaker than diopside in the dislocation creep regime.
Dynamics and storage of brine in mid‐ocean ridge hydrothermal systems
Authors: Fontaine Fabrice J. , Wilcock William S. D.
Published: June 2006

Mid‐ocean ridge hydrothermal systems are known to vent fluids with salinities substantially different from seawater as a result of phase separation and segregation of the resulting vapor and brine phases. Time series of vent temperature and salinity (chlorinity) show that some black‐smoker vent fields such as the Main Endeavour Field on the Juan de Fuca Ridge have vented fluids with salinities well below seawater for over a decade, which raises important questions concerning the fate of brines in these systems. One widely accepted model is that high‐density brines formed by supercritical phase separation sink to the base of hydrothermal systems, leading to the development of a two‐layer system in which a recirculating brine layer underlies a single‐pass seawater cell. We first present theoretical arguments to constrain the dynamics of such a deep brine layer in a system still undergoing phase separation, and we conclude that if brines are stored in a basal layer, they are unlikely to convect because they will be stably stratified. One consequence of this result is that the brine layer beneath black smoker systems has to be thin (<10 m) to match the high heat fluxes. However, estimates of the rate at which brines are accumulating in the crust below the main field on the Endeavour segment of the Juan de Fuca Ridge suggest that the brine layer is likely at least 100 m thick. To resolve this apparent paradox, we propose an alternative model. We argue that interfacial tensions between fluid and solid phases will likely favor the segregation of vapor into the main fractures and brine into the smaller fissures and backwaters. This allows the vapor to flow efficiently through the system and transport large heat fluxes while most of the porosity in the lower part of the system fills with brines. It is generally believed that the pressure gradients in mid‐ocean ridge hydrothermal systems are close to cold hydrostatic. At the high temperatures and pressures characteristic of the deeper parts of these systems, brines with salinities as high as 20 wt % NaCl have densities around 800–900 kg m−3 and will be buoyant in a cold‐hydrostatic system. Rather than sinking to the base of the system, it is possible that brines produced by supercritical phase separation rise slowly until they reach a level of neutral buoyancy as they cool or enter high‐permeability regions in which the pressure gradients decrease.
Winter water masses in the Gulf of St. Lawrence
Authors: Galbraith Peter S.
Published: June 2006

The first 9 years of data collected during a new late wintertime hydrographic survey of the Gulf of St. Lawrence are presented. They show colder conditions than those previously measured from ships that were likely biased toward warmer ice‐free waters. The total volume of cold water (<−1°C) varied interannually from 10 to 15 × 103 km3 and is a good predictor for the following summertime Cold Intermediate Layer index. The volume of cold and saline Labrador Shelf waters that flowed in through the Strait of Belle Isle is estimated using two temperature‐salinity criteria. It exhibits much stronger interannual variability than the total cold water volume, representing from 5% to as much as 30% of all cold surface waters. It was sometimes observed to reach the bottom in Mecatina Trough at more than 200 m depth, where deep waters are isolated from the rest of the gulf.
Processes governing the supply of iron to phytoplankton in stratified seas
Authors: Tagliabue Alessandro , Arrigo Kevin R.
Published: June 2006

The impact of iron speciation on phytoplankton dynamics in the marine environment is currently not well understood. In this study, we modified the existing CIAO model of the Ross Sea to include major aspects of iron chemistry and examined the processes governing the supply of iron to phytoplankton. We suggest that the melting of sea ice and ensuing stratification dictates the speciation and bioavailability of iron. Photoreduction is the key process governing the supply of bioavailable Fe to the resident phytoplankton of the Ross Sea. Access to organically complexed iron is of greater significance in strongly stratified waters dominated by diatoms than in weakly stratified waters dominated by Phaeocystis antarctica. Light may control phytoplankton taxonomic composition in the Ross Sea by impacting both photosynthetic performance and iron speciation. The efficiency with which iron fuels phytoplankton carbon incorporation is greater in seasonal ice zones than in permanently ice‐free waters. Therefore, changes in the physical structure of the Southern Ocean could impact iron bioavailability, independent of any change in iron supply.
Observations and simulations of receiver‐induced refractivity biases in GPS radio occultation
Authors: Beyerle G. , Schmidt T. , Wickert J. , Heise S. , Rothacher M. , König‐Langlo G. , Lauritsen K. B.
Published: June 2006

An analysis of 206,422 atmospheric refractivity profiles observed by the CHAMP georesearch satellite between 14 May 2001 and 30 June 2005 reveals significant biases compared to European Centre for Medium‐Range Weather Forecasts meteorological fields at altitudes below 5 km. The mean bias decreases down to −2% at altitudes below 2 km; in the Amazon region, positive biases exceeding +1% are observed. In order to identify bias contributions caused by the receiver signal tracking process an end‐to‐end simulation study implementing different signal tracking modes was performed. The end‐to‐end simulations are based on 1992 radiosonde profiles obtained regularly aboard R/V Polarstern since December 1982 and were conducted with four receiver models using closed‐loop, fly wheeling, and open‐loop signal tracking methods. The simulation results confirm that open‐loop tracking yields significantly smaller biases and standard deviations of the fractional refractivity errors compared to fly wheeling enabled receivers. In addition, we analyze closed‐loop tracking with a second‐order loop and demonstrate that similar reductions in biases and standard deviations can be obtained.
New evidence of warming propagating toward the Arctic Ocean
Authors: Walczowski Waldemar , Piechura Jan
Published: June 2006

The dramatic changes in the Arctic climate observed in recent years have generated an urgent need to investigate the Arctic Ocean's heat budget. Mooring data and synoptic observations in the Fram Strait (FS) region have shown that increasing amounts of heat have been transported into the Arctic Ocean (AO) in recent times. Here we present results from observations conducted in the West Spitsbergen Current (WSC) in summers 2000–2005. The study was motivated by the strong warm anomalies seen in the Atlantic Water (AW) layer over a large area of the WSC, and changes in the WSC structure. We conclude that the warm signal was only approaching the FS, and we expect that high heat transport through the strait will continue and be even higher than during the last 6 years, mostly due to increasing activity and temperature of the western branch of WSC.
A comparison of united atom, explicit atom, and coarse-grained simulation models for poly(ethylene oxide)
Authors: Chen Chunxia , Depa Praveen , Sakai Victoria García , Maranas Janna K. , Lynn Jeffrey W. , Peral Inmaculada , Copley John R. D.
Published: June 2006

We compare static and dynamic properties obtained from three levels of modeling for molecular dynamics simulation of poly(ethylene oxide) (PEO). Neutron scattering data are used as a test of each model’s accuracy. The three simulation models are an explicit atom (EA) model (all the hydrogens are taken into account explicitly), a united atom (UA) model (CH2 and CH3 groups are considered as a single unit), and a coarse-grained (CG) model (six united atoms are taken as one bead). All three models accurately describe the PEO static structure factor as measured by neutron diffraction. Dynamics are assessed by comparison to neutron time of flight data, which follow self-motion of protons. Hydrogen atom motion from the EA model and carbon/oxygen atom motion from the UA model closely follow the experimental hydrogen motion, while hydrogen atoms reinserted in the UA model are too fast. The EA and UA models provide a good description of the orientation properties of C–H vectors measured by nuclear magnetic resonance experiments. Although dynamic observables in the CG model are in excellent agreement with their united atom counterparts, they cannot be compared to neutron data because the time after which the CG model is valid is greater than the neutron decay times.
Simultaneous in situ electrochemical, surface plasmon optical, and atomic force microscopy measurements: Investigation of conjugated polymer electropolymerization
Authors: Baba Akira , Knoll Wolfgang , Advincula Rigoberto
Published: June 2006

We report the simultaneous in situ electrochemical, optical, and surface morphological studies of conjugated polymer ultrathin film formation using a novel combined electrochemical instrumentation–surface plasmon resonance spectroscopy–atomic force microscopy. The initial stages of the electropolymerization of poly(3,4-ethylenedioxythiophene) films on flat gold electrode/substrates were observed in all three experiments simultaneously. In addition to the electrochemical information obtained, the surface plasmon optical technique showed the deposition of the film, and provided electrochromic behavior of the deposited film. Simultaneously, atomic force microscopy gave surface morphological properties and domain growth of the film. The complementarity of the information obtained from the combined techniques is useful for the investigation of polymer growth mechanism between cyclic voltammetry and potentiostatic deposition methods.
Anomalous oxygen isotope enrichment in CO2 produced from O+CO: Estimates based on experimental results and model predictions
Authors: Pandey Antra , Bhattacharya S. K.
Published: June 2006

The oxygen isotope fractionation associated with O+CO→CO2 reaction was investigated experimentally where the oxygen atom was derived from ozone or oxygen photolysis. The isotopic composition of the product CO2 was analyzed by mass spectrometry. A kinetic model was used to calculate the expected CO2 composition based on available reaction rates and their modifications for isotopic variants of the participating molecules. A comparison of the two (experimental data and model predictions) shows that the product CO2 is endowed with an anomalous enrichment of heavy oxygen isotopes. The enrichment is similar to that observed earlier in case of O3 produced by O+O2 reaction and varies from 70‰ to 136‰ for O18 and 41‰ to 83‰ for O17. Cross plot of δO17 and δO18 of CO2 shows a linear relation with slope of ∼0.90 for different experimental configurations. The enrichment observed in CO2 does not depend on the isotopic composition of the O atom or the sources from which it is produced. A plot of Δ(δO17) versus Δ(δO18) (two enrichments) shows linear correlation with the best fit line having a slope of ∼0.8. As in case of ozone, this anomalous enrichment can be explained by invoking the concept of differential randomization/stabilization time scale for two types of intermediate transition complex which forms symmetric (O16C12O16) molecule in one case and asymmetric (O16C12O18 and O16C12O17) molecules in the other. The δC13 value of CO2 is also found to be different from that of the initial CO due to the mass dependent fractionation processes that occur in the O+CO→CO2 reaction. Negative values of Δ(δC13) (∼12.1‰) occur due to the preference of C12 in CO2* formation and stabilization. By contrast, at lower pressures (∼100torr) surface induced deactivation makes Δ(δC13) zero or slightly positive.
Electrical conductance of DNA molecules with varied density of itinerant π electrons
Authors: Gao Xu-Tuan , Fu Xue , Mei Liang-Mo , Xie Shi-Jie
Published: June 2006

The electrical transport of DNA is closely related to the density of itinerant π electrons because of the strong electron-lattice interaction. The resistivities of two typical DNA molecules [poly(dG)-poly(dC) and λ-DNA] with varied densities of itinerant π electrons are calculated. It is found that the dependence of the resistivity on the density of itinerant π electrons is symmetrical about the half-filling state of itinerant π electrons in poly(dG)-poly(dC). At the half-filling state, the Peierls phase transition takes place and poly(dG)-poly(dC) has a large resistivity. When the density of itinerant π electrons departs far from the half-filling state, the resistivity of poly(dG)-poly(dC) becomes small. For λ-DNA, there is no Peierls phase transition due to the aperiodicity of its base pair arrangement. The resistivity of poly(dG)-poly(dC) decreases with increasing length of the molecular chain, but the resistivity of λ-DNA increases with increasing length. The conducting mechanisms for poly(dG)-poly(dC) and a few λ-DNA molecules with varied densities of itinerant π electrons are analyzed.
Neutron-enhanced annealing of radiation damage formed by self-ion implantation in silicon
Authors: Kinomura A. , Chayahara A. , Mokuno Y. , Tsubouchi N. , Horino Y. , Yoshiie T. , Hayashi Y. , Xu Q. , Ito Y. , Ishigami R. , Yasuda K.
Published: June 2006

The annealing effect of neutron irradiation has been observed for radiation damage in self-ion implanted silicon. Si samples implanted with (0.5–2)×1015Si∕cm2 were neutron irradiated at 400°C with the total number of displacements of 8.8×10−3dpa. A heavily disordered (not amorphized) sample clearly showed damage annealing enhanced by the neutron irradiation. The annealing efficiency (the ratio of annealed defects to atomic displacements) was calculated to be 1.3 defects/displacement. This annealing efficiency was compared with the results of previous ion beam annealing studies.
Electrostrictive effect on electronic structures of carbon nanotubes
Authors: Tang Chun , Guo Wanlin , Guo Yufeng
Published: June 2006

The effect of axial electrostrictive deformation on the electronic properties of single walled carbon nanotubes (SWCNTs) is studied by the density functional theory. We find that the band structures of SWCNTs change in electric fields, and the change can be significantly enhanced by the electrostrictive deformation. The polarization of the orbital charge densities and the variation of the dipole moment are also enhanced by the electrostriction. The influence of chirality and size effect on these properties are also analyzed.
Postcricoid Pharyngeal Carcinoma Mimicking Bulbar Amyotrophic Lateral Sclerosis
Authors: Rubin Devon I.
Published: June 2006

Bulbar weakness, including dysarthria, dysphagia, or progressive respiratory weakness, occurs as the presenting feature in approximately 25% of patients with amyotrophic lateral sclerosis (ALS). Misdiagnosis of ALS in patients with progressive bulbar symptoms is uncommon. This report describes a 73-year-old man who had a 10-month history of progressive hoarseness, dysphagia, and respiratory failure. The initial diagnosis was bulbar ALS. Computed tomography of his neck identified a postcricoid squamous cell carcinoma, which was causing bilateral vocal cord paralysis. To the author's knowledge, postcricoid carcinoma has not been previously described as mimicking ALS but should be considered in the differential diagnosis of bulbar ALS.
Histone modification-dependent and -independent pathways for recruitment of checkpoint protein Crb2 to double-strand breaks
Authors: Du Li-Lin , Nakamura Toru M. , Russell Paul
Published: June 2006

Cellular responses to DNA damage involve the relocalization of checkpoint proteins to DNA double-strand breaks (DSBs). The fission yeast checkpoint mediator protein Crb2, a homolog of mammalian 53BP1, forms ionizing radiation-induced nuclear foci (IRIF). The IRIF formation by Crb2 requires histone H2A C-terminal phosphorylation and H4-K20 methylation. However, the relevance of Crb2 relocalization is uncertain, because neither histone modification is required for a checkpoint response. Here we show that these histone modifications cooperate in the same Crb2 recruitment pathway, which also requires the Tudor and BRCT motifs in Crb2. In the absence of these histone modifications, an alternative recruitment pathway is sufficient for checkpoint activation and accumulation of Crb2 at a persistent DSB generated by HO endonuclease. This parallel pathway requires a cyclin-dependent kinase phosphorylation site in Crb2 that mediates an association with another BRCT protein Cut5 (the TopBP1 homolog), which also accumulates at HO-induced DSBs. We propose that such dual recruitment mechanisms may be a common feature of DNA damage checkpoint mediators.
Polycomb-group proteins repressthe floral activator AGL19 in the FLC-independent vernalization pathway
Authors: Schönrock Nicole , Bouveret Romaric , Leroy Olivier , Borghi Lorenzo , Köhler Claudia , Gruissem Wilhelm , Hennig Lars
Published: June 2006

Polycomb-group (PcG) proteins form a cellular memory by maintaining developmental regulators in a transcriptionally repressed state. We identified a novel flowering gene that is under PcG control in Arabidopsis—the MADS-box gene AGL19. AGL19 expression is maintained at very low levels by the PcG proteins MSI1, CLF, and EMF2, and AGL19 is partly responsible for the early flowering phenotype of clf mutants. AGL19 chromatin is strongly enriched in trimethylation of Lys 27 on histone H3 (H3K27me3) but not in H3K9me2. Repressive H3K27me3 marks were reduced by decreased CLF or MSI1 levels and by prolonged cold, suggesting that the PcG proteins MSI1 and CLF repress AGL19 in the absence of cold. Ectopic expression of AGL19 strongly accelerates flowering, and agl19 mutants have a decreased response to vernalization, the promotion of flowering by prolonged cold. Epistasis analyses revealed that AGL19 works in the poorly characterized FLC-independent vernalization pathway and does not require SOC1 to function. In this pathway, prolonged cold relieves AGL19 from PcG repression by a mechanism that requires VIN3 but not VRN2. Elevated AGL19 levels activate LFY and AP1 and eventually cause flowering.
Caring or uncaring – meanings of being in an oncology environment
Authors: Edvardsson David , Sandman P.O. , Rasmussen Birgit
Published: June 2006

Aim.  This paper reports a study illuminating meanings of being in the physical environment of an oncology centre as narrated by patients, significant others and staff.

Background.  The physical environment of hospitals can convey different messages. For example, landscape pictures, plants and comfortable chairs can convey positive messages, while sparsely decorated and run‐down environments can convey negative values. Traditional healthcare environments may be experienced as unfamiliar, strange and alienating, fostering feelings of stress and vulnerability. The majority of research on care environments has employed experimental designs to test different environmental variables, for example sound, colour and architecture, in relation to patient outcomes such as recovery, pain and blood pressure. There is, however, little research‐based understanding of the meanings of being in these environments.

Methods.  A phenomenological hermeneutic approach was applied to analyse 17 interviews with patients, significant others and staff carried out during the spring of 2004 at an oncology centre in Sweden.

Findings.  The physical environment was found to influence experiences of care in four ways: first, by being a symbol expressing messages of death and dying, danger, shame and stigma, less social value and worth; second by containing symbols expressing messages of caring and uncaring, life and death; third, by influencing interaction and the balance between being involved and finding privacy; and fourth, by containing objects that could facilitate a shift of focus away from the self: being able to escape the world of cancer, and finding light in the midst of darkness. The comprehensive understanding illuminates the physical environment as not merely a place for caring, but as an important part of caring that needs to be accounted for in nursing care.

Conclusion.  To promote well‐being among patients, we need to ask ourselves if the environment imposes rather than eases suffering. Our findings also suggest the importance of not limiting our conceptions of nursing to nurse–patient relationships, but of using the therapeutic potential of the total environment in nursing care.
Exploring knowledge work and leadership in online midwifery communication
Authors: Brooks Fiona , Scott Peter
Published: June 2006

Aim. This paper reports a study to answer the following question: if given a user‐friendly online system, that enabled communication across the practice community, would midwives function as knowledge workers?

Background. Globally, the demand for quality‐led and innovative service delivery requires that nurses and midwives shift from being ‘information workers’, or passive receivers of managerial and organizational decisions, to become ‘knowledge workers’ who are able to create, lead and communicate service innovation and practice development. New communication technologies may offer a means for healthcare professionals to interact as knowledge workers and develop supportive communities of practice.

Methods. An online discussion forum was implemented as a low‐cost technological intervention, deploying existing hardware and a standard hospital intranet. The evaluation of the forum was constructed as case‐study organizational research. The totality of online communication, both traffic and content, was analysed over a 3‐month period (193 messages downloaded 2003/2004), and 15 in‐depth interviews were undertaken with forum users.

Findings. Given simple, facilitative, innovative technology, supported by a positive working culture and guided by effective leadership, midwives could function as ‘knowledge workers’, critically reflecting upon their practice and translating knowledge into action designed to achieve change in practice. Participation occurred across all staff grades, and midwives were predominantly supportive and facilitative towards the contributions made by colleagues.

Conclusion. Midwives may be well placed to exemplify the ‘ideal’ characteristics of the knowledge worker being demanded of modern healthcare professionals. The deployment of online interactive technologies as part of strategic vision to enhance knowledge work among healthcare professionals should be given attention within health systems.
Identity and resistance: why spiritual care needs ‘enemies’
Authors: Swinton John
Published: June 2006

Aims.  This paper explores certain key critiques of spirituality‐in‐nursing as they have been offered by people outside of the discipline. It argues that nurses have not taken seriously enough the recent criticism of the nature and role of spirituality in nursing. Not to listen to the ‘enemies’ of spirituality‐in‐nursing is to risk stagnation and a drift into obscurity.

Background.  The area of spirituality has become a growing field of interest for nurses and has produced a burgeoning body of research literature. Yet, whilst much has been written about the positive aspects of spirituality, nurses have offered almost no critique of the ways in which spirituality and spiritual care are understood, despite the fact that there are clearly certain key issues that require robust critique and thoughtful reflection. Almost all of the major criticisms of spirituality‐in‐nursing have come from people outside of the discipline of nursing. The paper argues that nurses need to listen carefully to the criticisms of spirituality and spiritual care offered by the ‘enemies’ of spiritual care in nursing. When listened to constructively, they highlight issues that are vital for the development and forward movement of this important area of nursing practice.

Methods.  Literature review and critical reflection on current critiques of spirituality in nursing practice.

Conclusions.  The paper concludes that nurses need to begin to develop spirituality as a specific field of enquiry with its own bodies of knowledge, methodologies, assumptions and core disciplines.

Relevance to clinical practice.  In listening to and taking seriously its ‘enemies’, nursing has the opportunity to establish spirituality as an important, creative and vibrant aspect of nursing practice that has the capacity to grow and respond constructively to its ‘enemies’, in ways that make whole‐person‐care a real possibility.
How general are positive relationships between plant population size, fitness and genetic variation?
Authors: LEIMU ROOSA , MUTIKAINEN PIA , KORICHEVA JULIA , FISCHER MARKUS
Published: June 2006

Relationships between plant population size, fitness and within‐population genetic diversity are fundamental for plant ecology, evolution and conservation. We conducted meta‐analyses of studies published between 1987 and 2005 to test whether these relationships are generally positive, whether they are sensitive to methodological differences among studies, whether they differ between species of different life span, mating system or rarity and whether they depend on the size ranges of the studied populations.

Mean correlations between population size, fitness and genetic variation were all significantly positive. The positive correlation between population size and female fitness tended to be stronger in field studies than in common garden studies, and the positive correlation between genetic variation and fitness was significantly stronger in DNA than in isoenzyme studies.

The strength and direction of correlations between population size, fitness and genetic variation were independent of plant life span and the size range of the studied populations. The mean correlations tended to be stronger for the rare species than for common species.

Expected heterozygosity, the number of alleles and the number or proportion of polymorphic loci significantly increased with population size, but the level of inbreedingFISwas independent of population size. The positive relationship between population size and the number of alleles and the number or proportion of polymorphic loci was stronger in self‐incompatible than in self‐compatible species. Furthermore, fitness and genetic variation were positively correlated in self‐incompatible species, but independent of each other in self‐compatible species.

The close relationships between population size, genetic variation and fitness suggest that population size should always be taken into account in multipopulation studies of plant fitness or genetic variation.

The observed generality of the positive relationships between population size, plant fitness and genetic diversity implies that the negative effects of habitat fragmentation on plant fitness and genetic variation are common. Moreover, the stronger positive associations observed in self‐incompatible species and to some degree in rare species, suggest that these species are most prone to the negative effects of habitat fragmentation.
CRB‐65 predicts death from community‐acquired pneumonia*
Authors: BAUER T. T. , EWIG S. , MARRE R. , SUTTORP N. , WELTE T. ,   THE CAPNETZ STUDY GROUP
Published: June 2006

Objective.  The study was performed to validate the CURB, CRB and CRB‐65 scores for the prediction of death from community‐acquired pneumonia (CAP) in both the hospital and out‐patient setting.

Design.  Data were derived from a large multi‐centre prospective study initiated by the German competence network for community‐acquired pneumonia (CAPNETZ) which started in March 2003 and were censored for this analysis in October 2004.

Setting.  Out‐ and in‐hospital patients in 670 private practices and 10 clinical centres.

Subjects.  Analysis was done for n = 1343 patients (n = 208 out‐patients and n = 1135 hospitalized) with all data sets completed for the calculation of CURB and repeated for n = 1967 patients (n = 482 out‐patients and n = 1485 hospitalized) with complete data sets for CRB and CRB‐65.

Intervention.  None. 30‐day mortality from CAP was determined by personal contacts or a structured interview.

Results.  Overall 30‐day mortality was 4.3% (0.6% in out‐patients and 5.5% in hospitalized patients, P < 0.0001). Overall, the CURB, CRB and CRB‐65 scores provided comparable predictions for death from CAP as determined by receiver–operator‐characteristics (ROC) curves. However, in hospitalized patients, CRB misclassified 26% of deaths as low risk patients. Availability of the CRB‐65 score (90%) was far superior to that of CURB (65%), due to missing blood urea nitrogen values (P < 0.001).

Conclusions.  Both the CURB and CRB‐65 scores can be used in the hospital and out‐patients setting to assess pneumonia severity and the risk of death. Given that the CRB‐65 is easier to handle, we favour the use of CRB‐65 where blood urea nitrogen is unavailable.