bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacterial hemolysins and leukotoxins affect target cells by forming large exogenous pores into their plasma membrane. Escherichia coli hemolysin a as a case example
Authors: Menestrina Gianfranco , Dalla Serra Mauro , Pederzolli Cecilia , Bregante Monica , Gambale Franco
Published: February 2005

Many bacteria include among their virulence factors exoproteins which exert leukocidal and cytolytic functions and have the ability to form pores in model membranes. We show that, at least in the case of the RTX hemolysin produced by Escherichia coli (HlyA), formation of pores in planar lipid membranes is parallelled by opening of strikingly similar channels in the plasma membrane of exposed macrophages. Formation of such lesions in leukocytes can give rise to a variety of effects leading altogether to a diminished immune response towards the invasive bacteria.
Refinement-oriented probability for CSP
Authors: Morgan Carroll , McIver Annabelle , Seidel Karen , Sanders J. W.
Published: February 2005

Jones and Plotkin give a general construction for forming a probabilistic powerdomain over any directed-complete partial order [Jon90, JoP89]. We apply their technique to the failures/divergences semantic model for Communicating Sequential Processes [Hoa85].

The resulting probabilistic model supports a new binary operator, probabilistic choice, and retains all operators of CSP including its two existing forms of choice. An advantage of using the general construction is that it is easy to see which CSP identities remain true in the probabilistic model. A surprising consequence however is that probabilistic choice distributes through all other operators; such algebraic mobility means that the syntactic position of the choice operator gives little information about when the choice actually must occur. That in turn leads to some interesting interaction between probability and nondeterminism.

A simple communications protocol is used to illustrate the probabilistic algebra, and several suggestions are made for accommodating and controlling nondeterminism when probability is present.
Hamartoma Involving the Pseudarthrosis Site in Patients with Neurofibromatosis Type 1
Authors: Mariaud-Schmidt Rocío P. , Rosales-Quintana Sergio , Bitar Emilio , Fajardo Daniel , Chiapa-Robles Gilberto , González-Mendoza Amado , Barros-Núñez Patricio
Published: February 2005

Congenital pseudarthrosis is a rare disease with variable clinical effects. The disease remains 1 of the most controversial pediatric entities in terms of etiopathogenesis, therapy, and prognosis. Between 0.5% and 2.2% of patients with neurofibromatosis demonstrate pseudarthrosis in any of the long bones. The exact origin of the lesion is even unclear; although several attempts have been made to determine the type of tissue involving the pseudarthrosis site, only fibrous tissue has been documented in different reports. We present 2 unrelated Mexican patients (male and female) with familial neurofibromatosis and congenital pseudarthrosis of the tibia and fibula. Histochemical and immunostain studies after surgical resection of the affected ends from the pseudarthrosis site of both patients showed a picture compatible with hamartoma. This is the first time when histologic evidence of hamartomatous tissue involving the pseudarthrosis site is presented.
Unusual Case of Mesenteric Venous Thrombosis Associated with Oral Contraceptive Use in an Adolescent Girl
Authors: Bailey Karen A. , Bass Juan , Nizalik Elizabeth , Jimenez Carmencita
Published: February 2005

A 16-year-old girl presented with hematochezia and abdominal pain. The patient developed a small bowel obstruction that required a laparotomy, which showed a segment of grossly infarcted small bowel with 3 perforations, localized abscesses, and creeping fat. Resection and an end-to-end anastomosis were performed. Pathologic examination showed underlying mesenteric venous thrombosis with no evidence of Crohn's disease. Hematology workup showed no evidence of a congenitally inherent hypercoagulable state. The use of oral contraceptives was the only predisposing factor identified.
No association between polymorphisms in three genes of cytochrome p450 family and paranoid schizophrenia in northern Chinese Han population
Authors: Jia Yanbin , Yu Xin , Zhang Boyu , Yuan Yanbo , Xu Qi , Shen Yucun , Shen Yan
Published: February 2005

We genotyped six SNPs in the genes of p450 family among paranoid schizophrenics and normal controls. All subjects are unrelated Han Chinese. Three showed polymorphic, and no significant differences in allele or genotype frequencies were detected between patients and controls. Thus we obtained no evidence for the involvement of the polymorphisms in paranoid schizophrenia in the population investigated.
Analogical reasoning in schizophrenic delusions
Authors: Simpson Jane , Done D. John
Published: February 2005

Purpose

Reasoning ability has often been argued to be impaired in people with schizophrenic delusions, although evidence for this is far from convincing. This experiment examined the analogical reasoning abilities of several groups of patients, including non-deluded and deluded schizophrenics, to test the hypothesis that performance by the deluded schizophrenic group would be impaired.

Subjects/materials

Eleven deluded schizophrenics, 10 depressed subjects, seven non-deluded schizophrenics and 16 matched non-psychiatric controls, who were matched on a number of key variables, were asked to solve an analogical reasoning task.

Results

Performance by the deluded schizophrenic group was certainly impaired when compared with the depressed and non-psychiatric control groups though less convincingly so when compared with the non-deluded schizophrenic group. The impairment shown by the deluded schizophrenic group seemed to occur at the initial stage of the reasoning task.

Discussion

The particular type of impairment shown by the deluded subjects was assessed in relation to other cognitive problems already researched and the implications of these problems on reasoning tasks and theories of delusions was discussed.
Docking and fusion of insulin secretory granules in SUR1 knock out mouse β‐cells observed by total internal reflection fluorescence microscopy
Authors: Kikuta Toshiteru , Ohara-Imaizumi Mica , Nakazaki Mitsuhiro , Nishiwaki Chiyono , Nakamichi Yoko , Tei Chuwa , Aguilar-Bryan Lydia , Bryan Joseph , Nagamatsu Shinya
Published: February 2005

To explore how the sulfonylurea receptor (SUR1) is involved in docking and fusion of insulin granules, dynamic motion of single insulin secretory granules near the plasma membrane was examined in SUR1 knock‐out (Sur1KO) β‐cells by total internal reflection fluorescence microscopy. Sur1KO β‐cells exhibited a marked reduction in the number of fusion events from previously docked granules. However, the number of docked granules declined during stimulation as a consequence of the release of docked granules into the cytoplasm vs. fusion with the plasma membrane. Thus, the impaired docking and fusion results in decreased insulin exocytosis from Sur1KO β‐cells.
Devolution and the Deepening of Democracy: Explaining Outcomes of Municipal Reform in Mexico
Authors: BARRACCA STEVEN
Published: February 2005

This article evaluates the implementation of Mexico's Municipal Reform of 1983 in three states: Chihuahua, Oaxaca and Yucatán. The research focuses on one element of the reform, the transfer of public services from the state to the municipal level. The case studies were selected to examine the impact of two key variables on reform outcomes: fiscal capacity and partisan control of state and municipal governments. Counter to expectations, the reform has not advanced more in municipalities with greater fiscal capacity. Also counter to expectations, there is no evidence that devolution advanced more in municipalities controlled by the opposition. This is due to the fact that state governors have a high degree of discretion that allows them to block implementation for partisan motives rather than rational/technical ones. The Municipal Reform of 1999 attempts to remedy this problem by limiting gubernatorial discretion while increasing the legal recourse municipalities have in soliciting the transfer of services. This recourse includes filing suit before the Mexican Supreme Court.
Ockham as a divine-command theorist
Authors: OSBORNE THOMAS M.
Published: February 2005

Although this thesis is denied by much recent scholarship, Ockham holds that the ultimate ground of a moral judgement's truth is a divine command, rather than natural or non-natural properties. God could assign a different moral value not only to every exterior act, but also to loving God. Ockham does allow that someone who has not had access to revelation can make correct moral judgements. Although her right reason dictates what God in fact commands, she need not know that God so commands. Ockham's divine-command theory plays an important role in the shift away from a nature-based ethics, and it anticipates contemporary problems concerning truth in meta-ethics.
Escaping hell: divine motivation and the problem of hell
Authors: BUCKAREFF ANDREI A. , PLUG ALLEN
Published: February 2005

We argue that it is most rational for God, given God's character and policies, to adopt an open-door policy towards those in hell – making it possible for those in hell to escape. We argue that such a policy towards the residents of hell should issue from God's character and motivational states. In particular, God's parental love ought to motivate God to extend the provision for reconciliation with Him for an infinite amount of time.
Solar variability, dimethyl sulphide, clouds, and climate
Authors: Larsen S. H.
Published: February 2005

It is proposed that Earth's climate may be modulated, in part, by changes in the flux of ultraviolet/blue light into the oceans. This occurs, at a range of timescales, through solar variability and from damage to the ozone layer. A conceptual model is presented where, through a number of synergistic processes and positive feedbacks, changes in the ultraviolet/blue flux alter the dimethyl sulphide flux to the atmosphere, and in turn the number of cloud condensation nuclei, cloud albedo, and thus sea surface temperature. The greatest effects are expected in the oligotrophic subtropical oceans, under the Hadley circulation, in summer.
Simultaneous radar observations of meter‐scale F region irregularities at and off the magnetic equator over India
Authors: Patra A. K. , Tiwari D. , Sripathi S. , Rao P. B. , Sridharan R. , Devasia C. V. , Viswanathan K. S. , Subbarao K. S. V. , Sekar R. , Kherani E. A.
Published: February 2005

Simultaneous observations of equatorial spread F irregularities made with an 18 MHz radar from Trivandrum, located at the geomagnetic equator, and a 53 MHz radar from Gadanki, located at a magnetic latitude of 6.5°N, corresponding to nearly the same longitude zone, are presented. The observations correspond to 8.3 and 2.8 m irregularities, respectively. The spread F irregularities at both the locations are found to occur nearly at the same time but are observed for longer duration at Gadanki than at Trivandrum. The spread F structures as observed in the intensity maps corresponding to Gadanki are characterized by multiple periodic plumes in contrast to a limited number of plumes observed over Trivandrum. The Doppler velocities associated with these irregularities corresponding to Trivandrum are in the range of −100–150 m s−1, whereas they are in the range of −100–250 m s−1 at Gadanki. Further, the fluctuating velocity fields are much stronger in the Gadanki observations than in the Trivandrum observations. Remarkably, the spectral widths are <100 m s−1 in Trivandrum observations in contrast to those observed at Gadanki with values as high as 300 m s−1. The observations are compared with those made elsewhere and are discussed in the light of current understanding of the meter‐scale irregularities responsible for the radar backscatter.
Statistical studies of auroral MF burst emissions observed at South Pole Station and at multiple sites in northern Canada
Authors: LaBelle J. , Weatherwax A. T. , Tantiwiwat M. , Jackson E. , Linder J.
Published: February 2005

Auroral MF burst is a broadband impulsive natural radio emission of auroral origin observed at ground level in the frequency range 0.8–4.5 MHz. Application of a semiautomated analysis method to data collected at South Pole Station, 74° magnetic latitude, results in a database of frequencies, amplitudes, and universal times of MF burst emissions observed during 1 January–31 December 2003. Besides confirming that MF burst emissions are observed at ground level only during darkness and that magnetic local time plays a significant role in controlling the MF burst occurrence rate, which maximizes in the pre‐magnetic‐midnight hours, these data reveal that the frequencies of MF burst emissions tend to be higher just after sunset and before sunrise than they are during midwinter. This observation supports a link between the emission frequency and the maximum plasma frequency in the ionosphere. South Pole data also show evidence for MF burst extending to frequencies well below the ionospheric gyrofrequency, which brings up the possibility that they are partly in the whistler mode. Analysis of optical and riometer data from one extra‐low‐frequency MF burst example suggests that MF burst is associated with a relatively high‐energy (>10 keV) auroral electron beam. Data from multiple Canadian observatories during 1997–1998 show that the MF burst occurrence rate maximizes near 74° magnetic latitude. With observatories spaced by 260–585 km, about 10% of the MF burst events are observed at two or more stations. Among coincident events, about 3/4 occur first at the lower‐latitude station and shift to the higher‐latitude station. The average duration of the MF burst events detected at two or more observatories increases with latitude.
Spin‐up and the effects of a submarine canyon: Applications to upwelling in Astoria Canyon
Authors: Mirshak R. , Allen S. E.
Published: February 2005

A parameterization for the on‐shelf mass flux induced by upwelling through a shelf break submarine canyon is estimated by laboratory spin‐up experiments. We determine the effects of a submarine canyon on flow evolution implicitly by measuring the topographic drag force in the context of a heuristic model. Trials were performed across a range of values for the shelf break velocity, Coriolis frequency, and buoyancy frequency. Assuming the drag force within the canyon is balanced locally by rotation, we propose a parameterization for upwelling through a canyon provided that the Coriolis frequency, buoyancy frequency, shelf break velocity, and canyon dimensions at the shelf break depth are known. We use our results to compare wind‐forced and canyon‐forced upwelling over Astoria Canyon off the coast of Washington State. The analysis suggests that canyon‐forced upwelling through Astoria Canyon is of equal importance to wind‐forced upwelling directly above it on seasonal scales.
Modeling reactive geochemical transport of concentrated aqueous solutions
Authors: Zhang Guoxiang , Zheng Zuoping , Wan Jiamin
Published: February 2005

Aqueous solutions with ionic strength larger than 1 M are usually considered concentrated aqueous solutions. These solutions can be found in some natural systems and are also industrially produced and released into accessible natural environments, and as such, they pose a big environmental problem. Concentrated aqueous solutions have unique thermodynamic and physical properties. They are usually strongly acidic or strongly alkaline, with the ionic strength possibly reaching 30 M or higher. Chemical components in such solutions are incompletely dissociated. The thermodynamic activities of both ionic and molecular species in these solutions are determined by the ionic interactions. In geological media the problem is further complicated by the interactions between the solutions and sediments and rocks. The chemical composition of concentrated aqueous solutions when migrating through the geological media may be drastically altered by these strong fluid‐rock interactions. To effectively model reactive transport of concentrated aqueous solutions, we must take into account the ionic interactions. For this purpose we substantially extended an existing reactive transport code, BIO‐CORE2D©, by incorporating a Pitzer ion interaction model to calculate the ionic activity. In the present paper, the model and two test cases of the model are briefly introduced. We also simulate a laboratory column experiment in which the leakage of highly alkaline waste fluid stored at Hanford (a U.S. Department of Energy site, located in Washington State) was studied. Our simulation captures the measured pH evolution and indicates that all the reactions controlling the pH evolution, including cation exchanges and mineral dissolution/precipitation, are coupled.
Origin and migration of dissolved organic carbon fractions in a clay‐rich aquitard: 14C and δ13C evidence
Authors: Hendry M. J. , Wassenaar L. I.
Published: February 2005

The origin and long‐term transport of dissolved organic carbon (DOC) and its high molecular weight (HMW) and low molecular weight (LMW) fractions were investigated in a clay‐rich till aquitard system. DOC concentrations decreased systematically with depth from 168 mg L−1 in the surficial fractured zone (1.2 m) to minimum values of 12–16 mg L−1 from 15 to 43 m depth in the nonfractured aquitard. The HMW and LMW DOC fractions and their corresponding δ13C values also decreased systematically with depth. Numerical transport simulations of the downward migration of DOC from the soil zone into the aquitard closely approximated field‐measured values and show transport of DOC was controlled by diffusive mixing. The depth trends for HMW and LMW DOC fractions and δ13C support hypothesized transport via diffusion, as well as earlier findings that microbial respiration in this nonfractured aquitard was negligible over the time period studied. The 14C content of the HMW DOC fraction decreased systematically with depth from 87 percent modern carbon (pmC) at 1.2 m to 13–15 pmC from 15 to 43 m depth. A simple model accounting for diffusive mixing and radioactive decay described the 14C profile in the aquitard. Radiocarbon measurements, transport modeling, and δ13C data suggest DOC and its fractions were derived from two distinct end‐members: soil organic carbon formed since the Holocene (∼10 ka B.P.) and DOC in connate pore water (∼15 ka B.P.).
Transport modeling of nonlinearly adsorbing solutes in physically heterogeneous pore networks
Authors: Acharya R. C. , Van der Zee S. E. A. T. M. , Leijnse A.
Published: February 2005

The purpose of this study is to upscale nonlinearly reactive transport from the pore scale to a heterogeneous porous medium with the aid of a sufficiently large three‐dimensional pore network model. We consider a porous medium that is chemically homogeneous (sorption reactivity is constant in space) but physically heterogeneous, as it has a spatially variable pore size. Our numerical experiments aim to assess whether traveling wave (TW) behavior develops and to assess how large a network is required to be to allow our conclusions. This study revealed that for this purpose the network should include more than a million pore units and that this size varies with the degree of heterogeneity. This assertion is based on temporal changes of the moments of a migrating front of nonlinearly adsorbing solute. In networks of equal sized pores, TW behavior occurs, and concentration distributions can be predicted by an analytical solution. For increasing physical heterogeneity the balance between the dispersive and adsorptive forces remains absent because the second central moment continues to grow as a function of time. The growth rate of this moment is a function of pore‐scale heterogeneity.
Infiltration in a double‐porosity medium: Experiments and comparison with a theoretical model
Authors: Lewandowska Jolanta , Szymkiewicz Adam , Gorczewska Wioletta , Vauclin Michel
Published: February 2005

This paper presents experimental verification of the mathematical model of unsaturated flow in double‐porosity soils developed by the asymptotic homogenization method. A series of one‐dimensional infiltration experiments was carried out in a column filled with a double‐porosity medium composed of a mixture of sand and sintered clayey spheres arranged in a periodic manner. The unsaturated hydraulic properties of each porous material were obtained from independent infiltration experiments by inverse analysis and some additional tests. They were used to calculate the effective parameters of the double‐porosity medium, i.e., the effective hydraulic conductivity and the effective capillary capacity. The numerical solution of the macroscopic boundary value problem, consisting of a highly nonlinear integrodifferential equation, was obtained using the Fortran code DPOR_1D presented by Lewandowska et al. [2004]. The calculated time evolutions of both water infiltrating into and flowing out from the double‐porosity medium were compared with the experimental results. A very reasonable qualitative and quantitative agreement between simulations and observations is obtained, showing the capacity of the model to capture the main features of the process.
Tryptase concentrations in bronchoalveolar lavage from patients with chronic eosinophilic pneumonia
Authors: BARGAGLI Elena , BIGLIAZZI Caterina , LEONINI Alessandra , NIKIFORAKIS Nikolaos , PERARI Maria G. , ROTTOLI Paola
Published: February 2005

In order to characterize BAL (bronchoalveolar lavage) in CEP (chronic eosinophilic pneumonia) and to investigate the possible role of mast cells and tryptase in the pathogenesis of this interstitial disease, cells and tryptase levels were determined in BAL of patients with CEP and in a group of healthy controls. The results show that a statistically significant increase in tryptase concentration was found in patients with CEP compared with the healthy controls. This is the first report that shows an increase in tryptase levels in CEP and could reflect higher mast cell activation as well as larger mast cell populations in the lungs of these patients. These results strongly support the involvement of mast cells and eosinophils in the immunopathogenesis of CEP.
Kinetics and mechanism of bimolecular electron transfer reaction in quinone-amine systems in micellar solution
Authors: Kumbhakar Manoj , Nath Sukhendu , Mukherjee Tulsi , Pal Haridas
Published: February 2005

Photoinduced electron transfer (ET) reactions between anthraquinone derivatives and aromatic amines have been investigated in sodium dodecyl sulphate (SDS) micellar solutions. Significant static quenching of the quinone fluorescence due to high amine concentration in the micellar phase has been observed in steady-state measurements. The bimolecular rate constants for the dynamic quenching in the present systems kqTR, as estimated from the time-resolved measurements, have been correlated with the free energy changes ΔG0 for the ET reactions. Interestingly it is seen that the kqTR vs ΔG0 plot displays an inversion behavior with maximum kqTR at around 0.7eV, a trend similar to that predicted in Marcus ET theory. Like the present results, Marcus inversion in the kqTR values was also observed earlier in coumarin-amine systems in SDS and TX-100 micellar solutions, with maximum kqTR at around the same exergonicity. These results thus suggest that Marcus inversion in bimolecular ET reaction is a general phenomenon in micellar media. Present observations have been rationalized on the basis of the two-dimensional ET (2DET) theory, which seems to be more suitable for micellar ET reactions than the conventional ET theory. For the quinone-amine systems, it is interestingly seen that kqTR vs ΔG0 plot is somewhat wider in comparison to that of the coumarin-amine systems, even though the maxima in the kqTR vs ΔG0 plots appear at almost similar exergonicity for both the acceptor-donor systems. These observations have been rationalized on the basis of the differences in the reaction windows along the solvation axis, as envisaged within the framework of the 2DET theory, and arise due to the differences in the locations of the quinones and coumarin dyes in the micellar phase.
Geometric collision rates and trajectories of cloud droplets falling into a Burgers vortex
Authors: Hill Reginald J.
Published: February 2005

Droplet velocities, concentrations, and geometric collision rates are calculated for droplets falling into Burgers vortices as a step toward understanding the role of turbulence-induced collisions of cloud water droplets. The Burgers vortex is an often used model of vortices in high Reynolds number turbulence. Droplet radii considered are 10, 20, and 40μm; those radii are relevant to warm rain initiation. A method of calculating the concentrations of droplets along their trajectories by means of differential geometry is derived and implemented. A generalization of the rate of geometrical collisions of inertial particles is derived; the formulation applies for any local vorticity and rate of strain, and the classic collision-rate formula is obtained in the process. The relative velocities of droplets of different radii and their spatial variation of concentration affects spatial variation of collision rate; greater variation exists for a stronger vortex. The physical effects included in the droplet equation of motion are inertia, gravity, viscous drag, pressure and shear stress, added mass, the history integral, and the lift force. The lift force requires calculation of droplet angular velocity, the equation for which contains rotational inertial and viscous drag. An initial condition is found that does not cause an impulse in the history integral. The important terms in the droplets’ equations of motion are found such that simpler approximate equations can be used. It is found that the lift force is negligible, the history integral is not. For smaller droplets in regions of lower vorticity, the time derivative of the difference of slip velocity and gravitationally induced drift velocity may be neglected. The present study suggests that acceleration-induced coalescence is most significant for droplets that are entrained into or formed within an intensifying vortex as distinct from falling toward the vortex.
Positron lifetime measurements by proton capture
Authors: Selim F. A. , Wells D. P. , Harmon J. F.
Published: February 2005

A positron lifetime spectroscopy (PLS) technique was developed using coincident γ rays induced by proton capture. Proton capture in some light elements induce coincident MeV γ rays, allowing positron lifetime to be measured. One γ quantum provides a start signal for the positron lifetime spectrometer, whereas the other γ quantum bombards the sample under investigation, generating a positron inside it through pair production. The stop signal is obtained from the detection of one of the two 511keV photons emitted from positron annihilation with the sample electrons. This new technique can extend PLS, which is a powerful tool to identify the size and concentration of defects, to thick materials and a broad range of applications. It also eliminates the source contribution from the measured spectra, which may lead to the identification of more defect types in a sample.
A secondary electron emission detector for measuring the intensity of synchrotron radiation
Authors: Nariyama Nobuteru , Taniguchi Shingo
Published: February 2005

A secondary electron emission detector can be used as a high-intensity radiation beam monitor because the absence of ion recombination extends the upper dose range of the monitor. The characteristics of saturation, linearity, sensitivity, reproducibility, and current stability of the monitor were measured with respect to synchrotron radiation from undulators at SPring-8. Thin aluminum-evaporated electrodes were used in a vacuum chamber. Linearity was observed at 1011–1013photons∕s between 10 and 30keV. Even at the highest intensity of 1015photons∕s, current linearity was achieved to some extent. Sensitivity ranged from 27to55pC∕Gy∕cm2, and increased with decreasing energy. During long irradiation, the current decreased gradually with time; the degree became larger with the dose. When irradiation was interrupted, however, the current recovered to its initial value at the next irradiation.
Synthesis and optical study of crystalline GaP nanoflowers
Authors: Liu B. D. , Bando Y. , Tang C. C. , Golberg D. , Xie R. G. , Sekiguchi T.
Published: February 2005

GaP nanoflowers composed of numerous GaP nanowires are synthesized through heating InP and Ga2O3 powders. Crystalline GaP nanowires growing from Ga-rich particles have a cubic structure, uniform diameters of ∼300nm, and lengths from several to tens of micrometers. Typically, an individual GaP nanowire displays a hexagonal prism-like morphology with ⟨111⟩ as the preferential growth direction. Cathodoluminescence measurements show that GaP nanoflowers and GaP nanowires emit at ∼600 and ∼750nm, respectively. Additional low-intensity emission peaks are observed for GaP nanoflowers at ∼450nm.
Frequency modulation of spin-transfer oscillators
Authors: Pufall M. R. , Rippard W. H. , Kaka S. , Silva T. J. , Russek S. E.
Published: February 2005

Spin-polarized dc electric current flowing into a magnetic layer can induce precession of the magnetization at a frequency that depends on current. We show that addition of an ac current to this dc bias current results in a frequency modulated (FM) spectral output, generating sidebands spaced at the modulation frequency. The sideband amplitudes and shift of the center frequency with drive amplitude are in good agreement with a nonlinear FM model that takes into account the nonlinear frequency-current relation generally induced by spin transfer. Single-domain simulations show that ac current modulates the cone angle of the magnetization precession, in turn modulating the frequency via the demagnetizing field. These results are promising for communications and signal processing applications of spin-transfer oscillators.
Transport of bromide in the Bainsvlei soil: Field experiment and deterministic/stochastic model simulation. I. Continuous water application
Authors: Tilahun Ketema , Botha J. F. , Bennie A. T. P.
Published: February 2005

A field-scale tracer study was carried out in a sandy loam Bainsvlei soil of South Africa. The objectives were to study the leaching of solutes in this soil and analyse the result using deterministic and stochastic solute transport models. A rainfall simulator was used to apply water and solution on an area 100 by 100 cm at a flux rate of 5.41 mm/h. A neutron probe access tube was drilled at the centre of the plot to a depth of 200 cm. Four tensiometers were installed at 30, 45, 90, and 120 cm depths. After steady-state condition was attained, a conservative tracer Br– was then applied as KBr at a rate of 13.5 g Br/m2. Soil samples were taken 10 times at 20-cm depth intervals to a depth of 160 cm and Br– concentration was analysed using ion chromatography. Transport parameters were determined using a convection–dispersion equation (CDE) and the stream tube model (STM).
The average Br– mass recovery was almost 100%. The average pore-water velocity determined from soil water balance was 2.08 cm/h. Pore-water velocities determined with CDE and STM were 2.24 cm/h and 2.20 cm/h, respectively. Bromide velocities of peak concentration and solute centre of mass were 2.05 cm/h and 2.02 cm/h, respectively. Generally, these results indicate that the Br– moved almost as a piston flow in this soil. The deterministic CDE and the stochastic STM performed almost equally well in estimating the transport parameters.
Predicting water balance in a sandy soil: model sensitivity to the variability of measured saturated and near saturated hydraulic properties
Authors: Oliver Y. M. , Smettem K. R. J.
Published: February 2005

Water balance modelling based on Richards’ equation requires accurate description of the soils’ hydraulic parameters. Unfortunately, these parameters vary spatially and temporally as well as between measurement techniques. For most field modelling exercises, the hydraulic parameters are obtained from a small number of measurements or predicted from soil properties using pedo-transfer functions. The effect of different measurement techniques on the description of soil hydraulic parameters has been the subject of many studies but the effect of the variability of the hydraulic parameters on the predicted water balance has not been widely investigated.
In this study we compared the hydraulic parameters obtained solely from laboratory measurements with those obtained from a rapid wet end field measurement technique, augmented by dry end laboratory data. The water balance was modelled using the laboratory and field hydraulic parameter sets and compared to field water contents measured by time domain reflectometry (TDR). In a sandy soil, we found the total profile water content to be well modelled by both hydraulic parameter datasets, but the water content at a specific depth was less well predicted using either of the measured parameter sets. The water content at a specific depth was under-predicted prior to the rainfall event and over-predicted after the rainfall, regardless of whether the hydraulic parameters were obtained from laboratory or field measurements. Generally, the hydraulic parameters that were obtained from the field measurements gave a closer fit to the measured TDR water contents.
The sensitivity of the modelled water balance to changes in the hydraulic parameters within the observed range of parameter values was also investigated. Parameter percentage coefficient of variation within measurement techniques ranged from 60% for air entry, he; 19% for residual water content, θr; 5% for slope of the water retention curve, n; and 7% for saturated water content, θs. The percentage differences between the parameters obtained from the laboratory and field measurement techniques for the topsoil and subsoil respectively were 47% and 50% for he, 100% for θr, 28% and 40% for n, and –14.4% and 4.0% for θs.
Modelling water content changes at a particular depth in the sandy soil was found to be most influenced by variations in θs, and n. Predicted water contents were also affected by the θr but less influenced by the saturated hydraulic conductivity, Ks. The he was the least influential parameter but also the most variable. This suggests that measurement of θs, related to bulk density changes caused by tillage, wheel compaction, and consolidation, is required for water balance studies. Generally, n had small variability between measurements at a particular depth, which is promising for the use of pedo-transfer functions related to soil texture.
Label-free detection of small-molecule–protein interactions by using nanowire nanosensors
Authors: Wang Wayne U. , Chen Chuo , Lin Keng-hui , Fang Ying , Lieber Charles M.
Published: February 2005

Development of miniaturized devices that enable rapid and direct analysis of the specific binding of small molecules to proteins could be of substantial importance to the discovery of and screening for new drug molecules. Here, we report highly sensitive and label-free direct electrical detection of small-molecule inhibitors of ATP binding to Abl by using silicon nanowire field-effect transistor devices. Abl, which is a protein tyrosine kinase whose constitutive activity is responsible for chronic myelogenous leukemia, was covalently linked to the surfaces of silicon nanowires within microfluidic channels to create active electrical devices. Concentration-dependent binding of ATP and concentration-dependent inhibition of ATP binding by the competitive small-molecule antagonist STI-571 (Gleevec) were assessed by monitoring the nanowire conductance. In addition, concentration-dependent inhibition of ATP binding was examined for four additional small molecules, including reported and previously unreported inhibitors. These studies demonstrate that the silicon nanowire devices can readily and rapidly distinguish the affinities of distinct small-molecule inhibitors and, thus, could serve as a technology platform for drug discovery.
Adolescent perceptions of friendship and their associations with individual adjustment
Authors: Burk William J. , Laursen Brett
Published: February 2005

This study of 282 dyads examines early- and mid-adolescents’ perceptions of friendship quality and their association with daily disagreements, self- and mother reports of behaviour problems, and school grades. Actor and partner analyses identify unique associations between perceptions of friendship quality and perceptions of daily conflict. Actor effects reveal links between friendship negativity and self-perceptions of conflict affective intensity, relationship impact, post-conflict interaction, and post-conflict separation, and between friendship positivity and self-perceptions of relationship impact. Partner effects reveal links between friendship negativity and partner perceptions of conflict outcomes. Perceptions of relationship quality were also associated with self- and mother reports of behaviour problems and with school grades, such that individual and dyadic views of friendship negativity were linked to detrimental outcomes. The worst outcomes tended to be reserved for dyads in which one or both friends reported high levels of relationship negativity.
Sibling aggression: Sex differences and parents’ reactions
Authors: Martin Jacqueline L. , Ross Hildy S.
Published: February 2005

Thirty-nine families were observed extensively at home when children were 21/2 and 41/2 years of age and again 2 years later. The Social Relations Model is used to investigate children’s sex differences in aggression and parents’ prohibiting aggression during sibling conflict. In the first observation period, boys engaged in more severe and mild physical aggression, grabbing, insulting, and property damage than girls. At Time 2, boys engaged in more mild physical aggression and insulting, than girls, but there were no sex differences in other forms of aggression. At Time 1, parents’ responses were relatively uninfluenced by the sex of the children. However, parents were more likely to prohibit mild physical aggression, grabbing, and property damage by and towards girls at the second time period. Conversely, parents showed more tolerance for boys’ mild physical aggression at Time 2, suggesting that this socialisation message may play a role in boys’ greater use of physical aggression both at home and with peers.
EAPP, a Novel E2F Binding Protein That Modulates E2F-dependent Transcription
Authors: Novy Michael , Pohn Regina , Andorfer Peter , Novy-Weiland Tina , Galos Barbara , Schwarzmayr Ludwig , Rotheneder Hans
Published: February 2005

E2F transcription factors play an essential role in cell proliferation and apoptosis and their activity is frequently deregulated in human cancers. In a yeast two-hybrid screen we identified a novel E2F-binding protein. Due to its strong phosphorylation we named it EAPP (e2F-associated phosphoprotein). EAPP is localized in the nucleus and interacts with E2F-1, E2F-2, and E2F-3, but not with E2F-4. Examination of a number of human cell lines revealed that EAPP levels are elevated in most transformed cells. Moreover, EAPP mRNA was detected in all investigated human tissues in varying amounts. EAPP is present throughout the cell cycle but disappears during mitosis. In transfection assays with reporters controlled by either an artificial E2F-dependent promoter or the murine thymidine kinase promoter, EAPP increased the activation caused by E2F-1 but not by E2F-4. Surprisingly, the promoter of the p14ARFgene, which was also activated by E2F-1, became repressed by EAPP. Overexpression of EAPP in U2OS cells resulted in a significant increase of cells in S-phase, whereas RNAi-mediated knock down of EAPP reduced the fraction of cells in S-phase. Taken together, these data suggest that EAPP modulates E2F-regulated transcription, stimulates proliferation, and may be involved in the malignant transformation of cells.
Amine terminated poly(ethylene glycol) benzoate modified epoxy networks
Authors: Samanta B.C. , Maity T. , Kar S. , Banthia A.K.
Published: February 2005

Purpose

To evaluate the efficiency of modifying epoxy resin using amine terminated poly(ethylene glycol) benzoate (ATPEGB) for improved toughness and to optimise the results of such a modification.

Design/methodology/approach

For effective toughening, various compositions were made by incorporating different concentrations of ATPEGB. The impact and adhesive strengths of the unmodified and modified epoxy networks were characterised.

Findings

The modification of epoxy resin using ATPEGB showed significant enhancement of impact and adhesive strengths over the unmodified one. The modification caused a chemical linkage between ATPEGB and resin which led not only to a phase separation but also to ensuring the intrinsically strong chemical bonds across the ATPEGB phase/resin matrix interface, which was the main cause to the improved impact and adhesive strengths. The optimum results were obtained at 12.5 phr (parts per hundred parts of epoxy resin) of modifier.

Research limitations/implications

The modifier, ATPEGB, used in the present context was synthesised from poly(ethylene glycol) (PEG) of molecular weight 600. Besides, it could be synthesised from PEG of molecular weight 200, 400, 4,000, 20,000 etc. In addition, the efficiency of modification of epoxy resin using these could also be studied.

Practical implications

The method developed provided a simple and practical solution to improving the toughness of cured epoxy.

Originality/value

The method for enhanced toughness of cured epoxy was novel and could find numerous applications in surface coating and adhesive.
Hsp20, a novel α‐crystallin, prevents Aβ fibril formation and toxicity
Authors: Lee Sungmun , Carson Kenneth , Rice‐Ficht Allison , Good Theresa
Published: February 2005

β‐Amyloid (Aβ) is a major protein component of senile plaques in Alzheimer's disease, and is neurotoxic when aggregated. The size of aggregated Aβ responsible for the observed neurotoxicity and the mechanism of aggregation are still under investigation; however, prevention of Aβ aggregation still holds promise as a means to reduce Aβ neurotoxicity. In research presented here, we show that Hsp20, a novel α‐crystallin isolated from the bovine erythrocyte parasite Babesia bovis, was able to prevent aggregation of denatured alcohol dehydrogenase when the two proteins are present at near equimolar levels. We then examined the ability of Hsp20 produced as two different fusion proteins to prevent Aβ amyloid formation as indicated by Congo Red binding; we found that not only was Hsp20 able to dramatically reduce Congo Red binding, but it was able to do so at molar ratios of Hsp20 to Aβ of 1 to 1000. Electron microscopy confirmed that Hsp20 does prevent Aβ fibril formation. Hsp20 was also able to significantly reduce Aβ toxicity to both SH‐SY5Y and PC12 neuronal cells at similar molar ratios. At high concentrations of Hsp20, the protein no longer displays its aggregation inhibition and toxicity attenuation properties. Size exclusion chromatography indicated that Hsp20 was active at low concentrations in which dimer was present. Loss of activity at high concentrations was associated with the presence of higher oligomers of Hsp20. This work could contribute to the development of a novel aggregation inhibitor for prevention of Aβ toxicity.
Poor lymphocyte recovery following CD34‐selected autologous peripheral blood stem cell transplantation for non‐Hodgkin's lymphoma
Authors: Diviné Marine , Boutolleau David , Delfau‐Larue Marie‐Hélène , Beaujean Françoise , Jouault Hélène , Reyes Felix , Kuentz Mathieu , Bensussan Armand , Farcet Jean‐Pierre , Boumsell Laurence
Published: February 2005

Positive selection of CD34+ cells in autologous grafts, designed to deplete tumour cells, also results in T‐cell depletion. To assess the reconstitution of the different lymphocyte subsets and of the T‐cell repertoire diversity following autologous transplantation of selected CD34+ peripheral blood stem cells (PBSC), we analysed sequential blood samples in eight patients autografted for advanced B‐cell non‐Hodgkin's lymphoma in a phase I–II pilot study. Although natural killer cell recovery was rapid, T‐ and B‐cell recovery was delayed with a median of 110/μl CD4+, 175/μl CD8+ T cells and 45/μl B cells at 12 months post‐transplant. The naive CD45RA+ T‐cell compartment was profoundly deficient up to 12 months for both CD4+ and CD8+ subsets. A transient expansion of memory CD8+CD45RO+ T cells consisting of an increased percentage of CD57+CD28− cells occurred within the first 3 months post‐transplant, but the memory CD4+CD45RO+ T cells remained far below the normal value. The CD8+CD28+ T‐cell subset did not recover. Using multiplex PCR analysis of the T‐cell receptor γ locus, we found that the repertoire diversity improved at 12 months after being poor and oligoclonal during the first 3 months post‐transplant. As shown by monoplex PCRγ analysis of every VJ combination, despite T‐cell depletion of the graft, mature T cells were carried over with the selected CD34+ PBSC and contributed to the T‐cell recovery after transplantation.
Mucosal expression of cyclooxygenase isoforms 1 and 2 is increased with worsening damage to the gastric mucosa
Authors: Bhandari P , Bateman A C , Mehta R L , Patel P
Published: February 2005

Aims : To test the hypothesis that both COX‐1 and COX‐2 expression in human gastric mucosa is up‐regulated in the presence of inflammation as seen in patients with gastritis and gastric ulcers.

Methods and results : We performed immunohistochemistry using COX‐1 and COX‐2 monoclonal antibodies on gastric biopsies from 59 patients with normal mucosa, gastritis and gastric ulcers. Expression of COX‐1 and COX‐2 was quantified using an intensity proportion scoring system. Expression of COX‐1 was primarily seen in the lamina propria mononuclear cells with some expression in deep gastric glands in the ulcer group. Expression of COX‐2 was primarily seen in the deep gastric glands with focal expression in the lamina propria mononuclear cells. We found a stepwise increase in the expression of both COX‐1 and COX‐2 as mucosal damage progressed from normal to gastritis to gastric ulcer.

Conclusions : We conclude that both COX‐1 and COX‐2 expression in the gastric mucosa are increased in the setting of gastritis and gastric ulceration. Although this increased expression may be due, at least in part, to an increase in inflammatory cell numbers, this study raises the possibility that both COX‐1 and COX‐2 are inducible, contrary to the traditionally held view of only COX‐2 being inducible.
Community psychiatric nursing: focus on effectiveness
Authors: CUNNINGHAM G. , SLEVIN E.
Published: February 2005

The focus for provision of mental health services is now the community in most developed countries. Different ways of organizing community mental health services are evident in the literature. Community psychiatric nurses (CPNs) have a key role to play in these services but the literature indicates that the CPN role varies from area to area within different models of service provision. This paper presents the findings of a study in which 13 service users and 15 CPNs in five focus groups discussed the effectiveness of mental health service. Selected staff and service users were chosen from a representative range of community mental health services across Northern Ireland. Service users expressed concern at the variety of CPN and other professional roles within multidisciplinary teams and some CPNs expressed dissatisfaction with their role and with role boundaries within teams. These findings suggest that further work is needed within community mental health services to ensure the role of the CPN remains effective and develops to meet the needs of service users.