bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Mn and Nb dopants on electric properties of chemical-solution-deposited BiFeO3 films
Authors: Chung Chin-Feng , Lin Jen-Po , Wu Jenn-Ming
Published: June 2006

Polycrystalline Mn-doped, Nb-doped, and pure BiFeO3 (BFO) films were fabricated via chemical solution deposition (CSD) method. Influence of Mn and Nb dopants on electric properties of BFO films were studied. The current density versus electric field (J-E) characteristics indicated that conduction mechanisms of Mn-doped, Nb-doped, and pure BFO films annealed at 500°C were Ohmic conduction, grain boundary limited conduction, and space charge limited conduction, respectively. The effect of Mn and Nb dopants on electric properties of BFO films was interpreted by defect chemistry and chemical reaction in the CSD process. The Nb dopant is effective in improving electrical properties of CSD-derived BFO films, while Mn is harmful in this respect.
Advanced testing of adhesion and friction with a microtribometer
Authors: Varenberg M. , Peressadko A. , Gorb S. , Arzt E. , Mrotzek S.
Published: June 2006

To optimize the tribological performance of miniaturized systems, adequate experimental means are needed. Current microtribometers suffer from inability to ensure parallel flat-on-flat contact and often experience metrological problems related to the geometry of the force sensing element. The present work demonstrates how these limitations can be removed in either homemade or commercial microtribometers by using a self-aligning system of specimen holders and an improved force sensor based on a symmetric design principle. Preliminary tests conducted on a polyvinylsiloxane∕glass tribopair confirm the satisfactory operation of the setup and show no effect of applied load on pull-off force and friction coefficient.
High-performance blue electroluminescence devices based on distyrylbenzene derivatives
Authors: Duan Yu , Zhao Yi , Chen Ping , Li Jiang , Liu Shiyong , He Feng , Ma Yuguang
Published: June 2006

Amorphous molecular, distyrylbenzene derivative 2,5,2′,5′,2″,5″-hexastyryl-[1,1′;4′,1″] terphenyl (HSTP) is sandwiched between NPB and Alq3 as blue light-emitting material in typical multilayer organic light-emitting devices, where NPB and Alq3 are 1,4-bis(1-naphylphenylamino)biphenyl and tris(8-hydroxyquinoline)aluminum, respectively. Formation of exciplex at the interface of NPB and HSTP layer is verified by study on photoluminescence and electroluminescence (EL) spectra. The performance of EL can be greatly improved by optimizations of devices; a pure blue device with Internationale de l’Eclairage coordination (0.16, 0.13), maximum brightness of 15830cd∕m2, and current efficiency of 4.88cd∕A is obtained.
Material structure and metastability of hydrogenated nanocrystalline silicon solar cells
Authors: Yue Guozhen , Yan Baojie , Ganguly Gautam , Yang Jeffrey , Guha Subhendu , Teplin Charles W.
Published: June 2006

We find that the volume fraction of amorphous component in hydrogenated nanocrystalline silicon intrinsic layers is not necessarily the determining factor for the light-induced metastability ofn-i-p solar cells. Small grains and/or intermediate range order may play an important role in improving the stability. The distribution of nanocrystallites along the growth direction is also important. Based on the findings, we have optimized the hydrogen dilution profiling for controlling the structural evolution and have reduced the light-induced degradation of solar cells. As a result, we have achieved initial and stable active-area efficiencies of 14.1% and 13.2%, respectively, using ana-Si:H/nc-Si:H/nc-Si:H triple-junction structure.
Electromechanically driven and sensed parametric resonance in silicon microcantilevers
Authors: Requa Michael V. , Turner Kimberly L.
Published: June 2006

We report on the design and experimental measurements of an integrated driving and sensing technique in parametrically excited silicon microcantilevers. The design involves actuation with axial Lorentz forces and sensing with magnetomotive forces, both of which are enabled by a chip-scale permanent magnet. In this demonstration the micromechanical parametric resonance is measured electrically. This system has applications to resonant parametric sensing.
Effect of point defect and Mn concentration in time-resolved differential reflection in GaMnAs
Authors: Kim Shin , Oh Eunsoon , Lee J. U. , Kim D. S. , Lee S. , Furdyna J. K.
Published: June 2006

We measured the transmission spectra and the time-resolved differential reflectivity ΔR in Ga1−xMnxAs for x⩽0.05 for several excitation wavelengths. The sign of ΔR in Ga1−xMnxAs (x=0.015 and x=0.03) was negative for photon energy larger than band gap at room temperature. The negative component of ΔR was explained by defect induced absorption and/or the reduction of exciton bleaching, rather than by the change in density of near band edge states associated with Mn incorporation. For Ga0.95Mn0.05As, absorption edge broadening was observed in the transmission spectra and the induced absorption effect was reduced by the screening of Mn local potential by photocarriers.
Effect of wire number on x-pinch discharges
Authors: Green J. S. , Bland S. N. , Collett M. , Dangor A. E. , Krushelnick K. , Beg F. N. , Ross I.
Published: June 2006

An investigation has been carried out into the x-ray emission and plasma dynamics of a “tabletop” x-pinch plasma generated by passing a 40ns, 35kA current pulse through two or four 5μm thick tungsten wires. It was found that a four-wire x pinch consistently resulted in an order of magnitude higher energy hard x-ray yield (>3.5keV) than a two-wire pinch. The total x-ray emission from a four-wire pinch also had a shorter pulse length such that the total x-ray power was increased by more than a factor of 2. Observations of x-pinch discharges driven by a higher energy 160kA, 80ns generator are also presented. In this case x pinches with two, four, and six wires were made using thicker aluminum and molybdenum wires and the number of wires is shown to play a significant role in the plasma dynamics. Increasing the number of wires enhanced the reproducibility of the discharge and the x-ray pulse.
Terahertz quantum cascade lasers with double-resonant-phonon depopulation
Authors: Williams Benjamin S. , Kumar Sushil , Qin Qi , Hu Qing , Reno John L.
Published: June 2006

We present two different terahertz quantum cascade laser (QCL) designs based on GaAs∕Al0.3Ga0.7As heterostructures that feature a depopulation mechanism of two longitudinal-optical phonon scattering events. This scheme is intended to improve high temperature operation by reducing thermal backfilling of the lower radiative state. The better of these two devices displays a threshold current density of 170A∕cm2 at 5K and lases up to 138K in pulsed mode and 105K in continuous-wave mode. However, contrary to expectation, we observed no improvement in temperature performance compared to single-resonant-phonon designs, which suggests that the thermal backfilling is not yet a limiting factor for high temperature terahertz QCL operation.
Single superconducting split-ring resonator electrodynamics
Authors: Ricci Michael C. , Anlage Steven M.
Published: June 2006

We investigate the microwave electrodynamic properties of a single superconducting thin film split-ring resonator (SRR). Transmission data showed a high-Q stop band for a single Nb SRR (Q∼4.5×104 at 4.2K) below Tc, and no such feature for a Cu SRR or closed Nb loops. Adding SRRs increased the bandwidth, but decreased the insertion loss of the features. Placing the Nb SRR into an array of wires produced a single, elementary negative-index passband (Q∼2.26×104 at 4.2K). Changes in the features due to the kinetic inductance were observed. Models for SRR permeability and wire dielectric response were used to fit the data.
Direct observation of the transition state of ultrafast electron transfer reaction of a radiosensitizing drug bromodeoxyuridine
Authors: Wang C.-R. , Hu A. , Lu Q.-B.
Published: June 2006

Replacement of thymidine in DNA by bromodeoxyuridine (BrdU) has long been known to enhance DNA damage and cell death induced by ionizing/UV radiation, but the mechanism of action of BrdU at the molecular level is poor understood. Using time-resolved femtosecond laser spectroscopy, we obtain the real-time observation of the transition state of the ultrafast electron transfer (ET) reaction of BrdU with the precursor to the hydrated electron, which is a general product in ionizing/UV radiation. The results show that the ET reaction is completed within 0.2picosecond (ps) after the electronic excitation, leading to the formation of a transition state BrdU*− with a lifetime of ∼1.5ps that then dissociates into Br− and a high reactive radical dU*. The present results can greatly enhance our understanding not only of the mechanism of BrdU as a radio-/photosensitizer but of the role of prehydrated electrons in electron-initiated processes in biological and environmental systems.
Analysis of the three-dimensional ordering of epitaxial Ge quantum dots using focused ion beam tomography
Authors: Kubis Alan J. , Vandervelde Thomas E. , Bean John C. , Dunn Derren N. , Hull Robert
Published: June 2006

Buried layers in quantum dot (QD) superlattices influence the position of QDs in the subsequently grown layers through strain field interactions. Since the strain interactions are complex, a three-dimensional reconstruction of the superlattice can enhance the fundamental understanding of self-organization mechanisms. We have studied the three-dimensional relationship of QDs using focused ion beam tomography. Analysis of the reconstruction is consistent with earlier models for self-organization. QDs on successive layers form above buried QDs. In certain cases, successive QDs in a column decrease in size, resulting in the elimination of the column while QDs in other columns grow in size.
Ferroelectricity in the Dion-Jacobson CsBiNb2O7 from first principles
Authors: Fennie Craig J. , Rabe Karin M.
Published: June 2006

We have studied ferroelectricity in Dion-Jacobson CsBiNb2O7 from first principles. Using group-theoretical analysis and first-principles density functional calculations of the total energy and phonons, we perform a systematic study of the energy surface around a paraelectric prototypic phase. Our results suggest that CsBiNb2O7 is a ferroelectric with a polarization of Ps=40μCcm−2. We propose further experiments to clarify this point.
Injection dependence of spontaneous radiative recombination in crystalline silicon: Experimental verification and theoretical analysis
Authors: Altermatt P. P. , Geelhaar F. , Trupke T. , Dai X. , Neisser A. , Daub E.
Published: June 2006

The radiative recombination coefficient B in crystalline bulk silicon is enhanced by the Coulomb attraction between electrons and holes. This effect is weakened at high carrier densities due to screening. We measure the resulting dependence of B on the free-carrier density (i) by reinterpreting published data and (ii) with photoluminescence and photovoltaic measurements. We calculate the Coulomb enhancement by determining the electron-hole pair correlation function at zero interparticle distance, assuming a Debye interaction potential. Both bound and scattering state contributions are fully taken into account. Due to screening, B decreases with increasing free-carrier density.
Seropositivity to rabbit haemorrhagic disease virus in non-target mammals during periods of viral activity in a population of wild rabbits in New Zealand
Authors: Henning J. , Davies P. R. , Meers J.
Published: June 2006

As part of a longitudinal study of the epidemiology of rabbit haemorrhagic disease virus (RHDV) in New Zealand, serum samples were obtained from trapped feral animals that may have consumed European rabbit (Oryctolagus cuniculus) carcasses (non-target species). During a 21-month period when RHDV infection was monitored in a defined wild rabbit population, 16 feral house cats (Felis catus), 11 stoats (Mustela erminea), four ferrets (Mustela furo) and 126 hedgehogs (Erinaceus europaeus) were incidentally captured in the rabbit traps. The proportions of samples that were seropositive to RHDV were 38% for cats, 18% for stoats, 25% for ferrets and 4% for hedgehogs. Seropositive non-target species were trapped in April 2000, in the absence of an overt epidemic of rabbit haemorrhagic disease (RHD) in the rabbit population, but evidence of recent infection in rabbits was shown. Seropositive non-target species were found up to 2.5 months before and 1 month after this RHDV activity in wild rabbits was detected. Seropositive predators were also trapped on the site between 1 and 4.5 months after a dramatic RHD epidemic in February 2001. This study has shown that high antibody titres can be found in non-target species when there is no overt evidence of RHDV infection in the rabbit population, although a temporal relationship could not be assessed statistically owning to the small sample sizes. Predators and scavengers might be able to contribute to localised spread of RHDV through their movements.
Monitoring change in the vertebrate fauna of central Queensland, Australia, over a period of broad-scale vegetation clearance, 1973—2002
Authors: Woinarski J. C. Z. , McCosker J. C. , Gordon G. , Lawrie B. , James C. , Augusteyn J. , Slater L. , Danvers T.
Published: June 2006

This study reports change in the bird, mammal and amphibian fauna of the Emerald district, central Queensland, as detected from comparison of an inventory study undertaken in 1973–76, with a resurvey undertaken in 2001–02. Over this period, the region was subjected to unusually high rates of vegetation clearance, with the extent of native vegetation declining from 87% to 41%. In Australia, and elsewhere, there are remarkably few such long-term longitudinal studies, and particularly so for those that sample the same sites using identical procedures, and for those undertaken in a region of such dramatic environmental change. The ability to detect change from this dataset is constrained by the relatively small number of survey sites (24–45 survey sites, depending upon the taxonomic group considered). The interpretation of change is also affected by very different climatic conditions between the baseline and resurvey. Higher rainfall in the baseline survey period contributed to the most evident change, a major reduction in the number of waterbirds. However, even with waterbirds excluded, there was a significant change in the bird assemblage across the set of survey sites between the two periods. There were significant increases for a number of typically grassland birds (e.g. red-backed fairy-wren (Malurus melanocephalus), brown quail (Coturnix ypsilophora)) and significant decreases for a range of typically forest or woodland birds (e.g. grey shrike-thrush (Colluricincla harmonica), spiny-cheeked honeyeater (Acanthagenys rufogularis), striped honeyeater (Plectorhyncha lanceolata), grey fantail (Rhipidura fuliginosa)). These changes were largely maintained even when the dataset was restricted to only those sites that remained uncleared: that is, changes were evident not only across the changing landscape as a whole but there were also significant (consequential) changes at uncleared sites. Most of the native mammal species that were recorded sufficiently often to test for change showed a pattern of decline. Again, for some species (pale field-rat (Rattus tunneyi), greater glider (Petauroides volans) and eastern grey kangaroo (Macropus giganteus)), this decline occurred even within uncleared woodland sites. The most notable change in the frog fauna was the major increase in the exotic cane toad (Bufo marinus), but there were also significant declines for two native frog species. These results suggest a general trajectory of decline in distinctive woodland species, and their broad-scale replacement by more commensal species (weedy generalists favoured by human modification of the landscape).
Fluctuating asymmetry of the frog Crinia signifera in response to logging
Authors: Lauck Bonnie
Published: June 2006

Fluctuating asymmetry has been proposed as an indicator of environmental stress and population health. However, a notable feature of research examining the relationship between fluctuating asymmetry and population fitness is that of inconsistency. Logging dramatically alters habitat and has the potential to increase or decrease environmental stress. To evaluate the response of fluctuating asymmetry to logging, I conducted research to determine whether fluctuating asymmetry differs in the frog Crinia signifera captured at logged and unlogged sites and if any differences were correlated with body size or body condition. There was a decrease in fluctuating asymmetry but also a decrease in body size and body condition as a result of logging. I also investigated whether any relationship existed between the subtle asymmetry of individuals and the following indicators of fitness: clutch size, clutch mass, average egg mass, testes size, body size and body condition. There was no significant relationship between subtle asymmetry and the fitness indicators.
An assessment of the audibility of sound from human transport by breeding Weddell seals (Leptonychotes weddellii)
Authors: Petel Tamara D. van Polanen , Terhune John M. , Hindell Mark A. , Giese Melissa A.
Published: June 2006

Anthropogenic noise generated through travel in the Antarctic has the potential to affect the region’s wildlife. Weddell seals (Leptonychotes weddellii) in particular can be exposed to anthropogenic noise because they live under, and breed on, the fast ice on which humans travel. To investigate the potential effects of anthropogenic noise on Weddell seals we developed sound profiles for pedestrian travel, over-snow vehicles, aircraft and watercraft operating at various distances and altitudes from breeding seals. The received 1/3-octave noise levels were then related to an assumed detection threshold for the Weddell seal. We found that most noise levels generated by the pedestrian, quad (4-wheeled, all-terrain vehicle) and Hagglunds (tracked, all-terrain vehicle) were commonly categorised in the inaudible and barely audible range of detection (both in-air and underwater), while noise levels generated by the helicopter, Twin Otter aircraft and Zodiac boat were categorised more commonly in the barely audible and clearly audible range. Experimental underwater recordings of vocal behaviour of Weddell seals exposed to continuous low-amplitude over-snow vehicle noise (i.e. Hagglund operation) were also made. Weddell seals underwater did not alter individual call types in response to low-level Hagglunds noise, but they did decrease their calling rate.
Do tropical savanna skink assemblages show a short-term response to low-intensity fire?
Authors: Nicholson Evelyn , Lill Alan , Andersen Alan
Published: June 2006

The composition of skink assemblages at a tropical savanna site in northern Australia was documented immediately before and after low-intensity, experimental fires in the early dry season (June), and compared with the composition in neighbouring unburnt plots. The composition of the assemblage of captured skinks was not significantly affected by fire, and no change in total abundance of skinks was recorded. Arthropods constitute the principal food of the skinks and the composition of the captured arthropod samples on the treatment plots was significantly affected by the fires, with spiders, beetles and hemipterans increasing in numbers during the immediate post-fire period. Seasonal changes in captured skink assemblage composition, unrelated to the fire event, occurred between the wet–dry season transition and the early dry season. These changes were associated with variation in four weather variables and were possibly also related to seasonal reproductive activity. Our study demonstrates a high degree of resilience of savanna skinks to individual fire events; however, the longer-term effect of different fire regimes requires further investigation.
Population genetic tools for pest management: a review
Authors: Rollins Lee Ann , Woolnough Andrew P. , Sherwin William B.
Published: June 2006

Population genetic tools have the potential to answer key questions in pest management including quantifying the number of genetically distinct populations represented in an invasion, the number of individuals present, whether populations are expanding or contracting, identifying the origin of invasive individuals, the number of separate introduction events that have occurred and in which order, and the rate that individuals are moving between populations. Genetic methods have only recently gained sufficient resolution to address these questions due to advances in laboratory techniques coupled with an increase in computational power. In combination, these methods may lead to a more comprehensive understanding of the dynamics of invasions. The expansion of the European starling (Sturnus vulgaris) into Western Australia is used as an applied example of how genetic methods can be integrated to provide vital information to improve pest-management strategies. Invasion events also may provide a unique opportunity to test some of these methodologies.
A high-throughput gene knockout procedure for
Neurospora
reveals functions for multiple transcription factors
Authors: Colot Hildur V. , Park Gyungsoon , Turner Gloria E. , Ringelberg Carol , Crew Christopher M. , Litvinkova Liubov , Weiss Richard L. , Borkovich Katherine A. , Dunlap Jay C.
Published: June 2006

The low rate of homologous recombination exhibited by wild-type strains of filamentous fungi has hindered development of high-throughput gene knockout procedures for this group of organisms. In this study, we describe a method for rapidly creating knockout mutants in which we make use of yeast recombinational cloning,
Neurospora
mutant strains deficient in nonhomologous end-joining DNA repair, custom-written software tools, and robotics. To illustrate our approach, we have created strains bearing deletions of 103
Neurospora
genes encoding transcription factors. Characterization of strains during growth and both asexual and sexual development revealed phenotypes for 43% of the deletion mutants, with more than half of these strains possessing multiple defects. Overall, the methodology, which achieves high-throughput gene disruption at an efficiency >90% in this filamentous fungus, promises to be applicable to other eukaryotic organisms that have a low frequency of homologous recombination.
Regulation of Maximal Open Probability Is a Separable Function of Cavβ Subunit in L-type Ca2+ Channel, Dependent on NH2 Terminus of α1C (Cav1.2α)
Authors: Kanevsky Nataly , Dascal Nathan
Published: June 2006

β subunits (Cavβ) increase macroscopic currents of voltage-dependent Ca2+ channels (VDCC) by increasing surface expression and modulating their gating, causing a leftward shift in conductance–voltage (G-V) curve and increasing the maximal open probability, Po,max. In L-type Cav1.2 channels, the Cavβ-induced increase in macroscopic current crucially depends on the initial segment of the cytosolic NH2 terminus (NT) of the Cav1.2α (α1C) subunit. This segment, which we term the “NT inhibitory (NTI) module,” potently inhibits long-NT (cardiac) isoform of α1C that features an initial segment of 46 amino acid residues (aa); removal of NTI module greatly increases macroscopic currents. It is not known whether an NTI module exists in the short-NT (smooth muscle/brain type) α1C isoform with a 16-aa initial segment. We addressed this question, and the molecular mechanism of NTI module action, by expressing subunits of Cav1.2 in Xenopus oocytes. NT deletions and chimeras identified aa 1–20 of the long-NT as necessary and sufficient to perform NTI module functions. Coexpression of β2b subunit reproducibly modulated function and surface expression of α1C, despite the presence of measurable amounts of an endogenous Cavβ in Xenopus oocytes. Coexpressed β2b increased surface expression of α1C approximately twofold (as demonstrated by two independent immunohistochemical methods), shifted the G-V curve by ∼14 mV, and increased Po,max 2.8–3.8-fold. Neither the surface expression of the channel without Cavβ nor β2b-induced increase in surface expression or the shift in G-V curve depended on the presence of the NTI module. In contrast, the increase in Po,max was completely absent in the short-NT isoform and in mutants of long-NT α1C lacking the NTI module. We conclude that regulation of Po,max is a discrete, separable function of Cavβ. In Cav1.2, this action of Cavβ depends on NT of α1C and is α1C isoform specific.
An Electrically Coupled Network of Skeletal Muscle in Zebrafish Distributes Synaptic Current
Authors: Luna Victor M. , Brehm Paul
Published: June 2006

Fast and slow skeletal muscle types are readily distinguished in larval zebrafish on the basis of differences in location and orientation. Additionally, both muscle types are compact, rendering them amenable to in vivo patch clamp study of synaptic function. Slow muscle mediates rhythmic swimming, but it does so purely through synaptic drive, as these cells are unable to generate action potentials. Our patch clamp recordings from muscle pairs of zebrafish reveal a network of electrical coupling in slow muscle that allows sharing of synaptic current within and between segmental boundaries of the tail. The synaptic current exhibits slow kinetics (τdecay ∼4 ms), which further facilitates passage through the low pass filter, a consequence of the electrically coupled network. In contrast to slow muscle, fast skeletal muscle generates action potentials to mediate the initial rapid component of the escape response. The combination of very weak electrical coupling and synaptic kinetics (τdecay <1 ms) too fast for the network low pass filter minimizes intercellular sharing of synaptic current in fast muscle. These differences between muscle types provide insights into the physiological role(s) of electrical coupling in skeletal muscle. First, intrasegmental coupling among slow muscle cells allows effective transfer of synaptic currents within tail segments, thereby minimizing differences in synaptic depolarization. Second, a fixed intersegmental delay in synaptic current transit, resulting from the low pass filter properties of the slow muscle network, helps coordinate the rostral–caudal wave of contraction.
Mechanism of the Inhibition of Ca2+-Activated Cl− Currents by Phosphorylation in Pulmonary Arterial Smooth Muscle Cells
Authors: Angermann Jeff E. , Sanguinetti Amy R. , Kenyon James L. , Leblanc Normand , Greenwood Iain A.
Published: June 2006

The aim of the present study was to provide a mechanistic insight into how phosphatase activity influences calcium-activated chloride channels in rabbit pulmonary artery myocytes. Calcium-dependent Cl− currents (IClCa) were evoked by pipette solutions containing concentrations between 20 and 1000 nM Ca2+ and the calcium and voltage dependence was determined. Under control conditions with pipette solutions containing ATP and 500 nM Ca2+, IClCa was evoked immediately upon membrane rupture but then exhibited marked rundown to ∼20% of initial values. In contrast, when phosphorylation was prohibited by using pipette solutions containing adenosine 5′-(β,γ-imido)-triphosphate (AMP-PNP) or with ATP omitted, the rundown was severely impaired, and after 20 min dialysis, IClCa was ∼100% of initial levels. IClCa recorded with AMP-PNP–containing pipette solutions were significantly larger than control currents and had faster kinetics at positive potentials and slower deactivation kinetics at negative potentials. The marked increase in IClCa was due to a negative shift in the voltage dependence of activation and not due to an increase in the apparent binding affinity for Ca2+. Mathematical simulations were carried out based on gating schemes involving voltage-independent binding of three Ca2+, each binding step resulting in channel opening at fixed calcium but progressively greater “on” rates, and voltage-dependent closing steps (“off” rates). Our model reproduced well the Ca2+ and voltage dependence of IClCa as well as its kinetic properties. The impact of global phosphorylation could be well mimicked by alterations in the magnitude, voltage dependence, and state of the gating variable of the channel closure rates. These data reveal that the phosphorylation status of the Ca2+-activated Cl− channel complex influences current generation dramatically through one or more critical voltage-dependent steps.
Janitors and Sweatshop Citizenship in Canada
Authors: Aguiar Luis L M
Published: June 2006

Janitors in Canada increasingly suffer from what I call here “sweatshop citizenship”, which is a combination of disintegrating workplace rights and eroding social citizenship rights. This condition has been institutionalized by neoliberal state policies which have undermined the welfare state and the assumptions of citizenship which it embodied. Through an exploration of how sweatshop citizenship is being instituted in Ontario and British Columbia, I consider the difficulties which contemporary industrial practices in the cleaning industry and anti‐union legislation are presenting janitors, together with the possibility for their resisting such conditions.
Work Design and the Labouring Body: Examining the Impacts of Work Organization on Danish Cleaners’ Health
Authors: Søgaard Karen , Blangsted Anne Katrine , Herod Andrew , Finsen Lotte
Published: June 2006

Globalization and neoliberalism are having significant impacts upon the cleaning industry, as in the drive for greater work “efficiency”. One way in which cleaning companies have sought to increase efficiency is through the introduction of new equipment and forms of work organization. However, such moves appear to be having negative impacts upon cleaners’ bodies, and many report significant work‐related health problems. In light of this, here we explore the bodily consequences of two possible strategies for giving cleaners a healthier workday—increasing variation within cleaners’ current work tasks or allowing them to engage in a broader range of tasks through job enlargement. Drawing upon a literature review performed as part of a recent European Union project concerning the degree of physical strain to which cleaners are exposed during cleaning, a Danish laboratory study focusing on the loads to which cleaners’ shoulder muscles, backs, and hearts were exposed by different cleaning tasks, and a field study investigating the effects of job enlargement in Danish hospitals, we show that cleaning work is characterized by repetitive work for the muscles of the body's upper extremities and by high levels of dynamic and static force upon these muscles, regardless of which modes of cleaning (old or new style of cleaning tools) are used. Equally, monitoring of heart rates and assessment of the psychosocial environment suggest that simply interchanging current cleaning tasks does not provide sufficient variation in cleaners’ work to prevent work‐related musculoskeletal or cardiovascular damage, nor to create a less mentally stressful work environment. Although introducing greater work variation through job enlargement (such as combining cleaning with kitchen and portering tasks) is often presented as an effective way to minimize musculoskeletal and cardiovascular damage, our field study shows that even this does not provide sufficient variation in physical work conditions, although improvement in some cleaners’ mental health was noted. Therefore, we conclude, prevention of musculoskeletal and cardiovascular disorders demands a much more comprehensive strategy of work redesign than that proposed by some employers and government agencies. Whether this is likely, given competitive pressures towards increased outsourcing and privatization, is, of course, the question.
Cleaners’ Organizing in Britain from the 1970s: A Personal Account
Authors: Rowbotham Sheila
Published: June 2006

In the early 1970s the Women's Liberation Movement in Britain set out to unionize night cleaners. A long and intensive campaign resulted in two strikes and a greater awareness in the trade union movement about this neglected group of workers. But though the publicity generated by newspaper articles, meetings, and the making of two documentary films on cleaners focused attention on their conditions, organization proved very difficult. This was compounded by the economic and political climate from the late 1970s and the impact of privatization, which contributed to the growth in inequality in British society. This article outlines a disregarded history of attempts to organize cleaners, a history which is gaining a new‐found relevance in the wake of the “Justice for Janitors” campaign in the US and the awareness that low‐paid service work plays a key part in the global economy.
The Privatization of Health Care Cleaning Services in Southwestern British Columbia, Canada: Union Responses to Unprecedented Government Actions
Authors: Cohen Marcy
Published: June 2006

This paper analyzes the political dynamics between a newly elected, right‐leaning provincial government and a left‐leaning public sector union that resulted in the privatization of 4000 health support housekeeping jobs in southwestern British Columbia in less than a year. The article documents how government set the stage for privatization, the struggle that ensued when the union resisted concessionary bargaining, and the new challenges that emerged for both union and management once housekeeping and other support services were taken over by multi‐national service corporations. This case is significant because the size and scope of this privatization and the legislation that facilitated it are unprecedented in Canadian history.
The efficacy of corticosteroid therapy in inflammatory bowel disease: analysis of a 5‐year UK inception cohort
Authors: HO G.‐T. , CHIAM P. , DRUMMOND H. , LOANE J. , ARNOTT I. D. R. , SATSANGI J.
Published: June 2006

Background

Corticosteroids remain the mainstay of first‐line therapy in active inflammatory bowel disease.

Aims

To determine the clinical outcome after the first corticosteroid‐therapy and to identify factors which predict response/failure.

Methods

216 (136 ulcerative colitis and 80 Crohn's disease) patients were identified in this 5‐year inception cohort. The outcomes of early (30 days) and late (1 year) responses were used. Multivariate analyses were performed to identify factors associated with outcome.

Results

86 (63%) and 60 (75%) ulcerative colitis and Crohn's disease required corticosteroid therapy, respectively. In ulcerative colitis, at 30 days, 69 (51%), 42 (31%) and 25 (18%) patients demonstrated complete response, partial response and no response, respectively. For Crohn's disease, these outcomes were observed in 32 (40%), 28 (35%) and 20 (25%). After 1 year, 75 (55%), 23 (17%) and 29 (21%) patients with ulcerative colitis demonstrated prolonged response, corticosteroid‐dependence or required surgery, respectively. For Crohn's disease, these outcomes were observed in 30 (38%), 19 (24%) and 27 (35%) patients. Extensive ulcerative colitis was a predictor of surgery (P = 0.001, OR: 15.2). In Crohn's disease, inflammatory disease behaviour was negatively associated with surgery (P = 0.02, OR: 0.13).

Conclusion

Although corticosteroids are effective, dependence/resistance remains common. Patients with extensive ulcerative colitis and fistulizing/stricturing Crohn's are most at risk of failing corticosteroid therapy.
Adverse events leading to modification of therapy in a large cohort of patients with inflammatory bowel disease
Authors: HINDORF U. , LINDQVIST M. , HILDEBRAND H. , FAGERBERG U. , ALMER S.
Published: June 2006

Background

Adverse events leading to discontinuation or dose reduction of thiopurine therapy occur in 9–28% of patients with inflammatory bowel disease.

Aims

To evaluate the influence of thiopurine methyltransferase status and thiopurine metabolites in a large patient population for the risk of developing adverse event.

Methods

Three hundred and sixty‐four patients with inflammatory bowel disease and present or previous thiopurine therapy were identified from a local database.

Results

The adverse event observed in 124 patients (34%) were more common in adults than children (40% vs. 15%; P < 0.001) and in low to intermediate (≤9.0 U/mL red blood cell) than normal thiopurine methyltransferase activity (P = 0.02). Myelotoxicity developed later than other types of adverse event. An increased frequency of adverse event was observed in patients with tioguanine (thioguanine) nucleotide above 400 or methylated thioinosine monophosphate above 11 450 pmol/8 × 108 red blood cell. A shift to mercaptopurine was successful in 48% of azathioprine‐intolerant patients and in all cases of azathioprine‐induced myalgia or arthralgia.

Conclusions

A pre‐treatment determination of thiopurine methyltransferase status might be appropriate as patients with low to intermediate thiopurine methyltransferase activity are more prone to develop an adverse event; determination of metabolite levels can be useful in the case of an adverse event. Mercaptopurine therapy should be considered in azathioprine‐intolerant patients.
Infliximab therapy in Crohn's disease: a pragmatic approach?
Authors: KEVANS D. , KEEGAN D. , MULCAHY H. E. , O'DONOGHUE D. P.
Published: June 2006

Background

Infliximab is recognized as an effective therapy in unresponsive luminal and fistulating Crohn's disease. The use of maintenance or ‘on demand’ therapy thereafter is controversial.

Aim

To assess the need for maintenance infliximab therapy in a clinical setting where immunomodulatory agents are widely used and where episodic therapy is used in preference to maintenance therapy.

Methods

Ninety‐three patients with Crohn's disease receiving infliximab; 72 with unresponsive luminal disease and 21 with fistulous disease. Data collected included disease site and duration, surgical and smoking history, initial response rates, duration of response maintenance and concomitant medications.

Results

Fifty‐six of 72 (78%) patients with luminal disease and 11 of 21 (52%) with fistulous disease achieved an initial response. Ten of 67 responders required conversion to maintenance infliximab infusions, while 31 remain in remission. Patients with luminal disease and those who had not taken previous surgery had higher response rates to infliximab. Younger patients and those with small bowel disease had higher relapse rates following initial response. Three patients developed allergic reactions to infliximab and one patient died of progressive pulmonary disease 6 weeks after their first infusion.

Conclusions

Many patients with Crohn's disease can be maintained successfully with an episodic infliximab regimen.
Review article: moderate sedation for endoscopy: sedation regimens for non‐anaesthesiologists
Authors: REX D. K.
Published: June 2006

Background

Moderate sedation is a drug‐induced depression of consciousness during which patients respond purposefully to verbal commands with or without light tactile stimulation. Moderate sedation is typically accepted in the anaesthesia community as an appropriate target for sedation by non‐anaesthesiologists.

Aim

To describe drug regimens that can be successfully and safely targeted to moderate sedation for endoscopy by non‐anaesthesiologists.

Results

Moderate sedation can be achieved using narcotics and benzodiazepines. There is interest in some countries in propofol for endoscopy, which is often viewed as an agent for deep sedation. Indeed, propofol cannot be targeted to moderate sedation for endoscopy as a single agent because of coughing during upper endoscopy and pain withdrawal responses during colonoscopy. Pre‐treatment with low doses of narcotic and/or benzodiazepine blocks these effects, allowing propofol to be targeted to moderate sedation. Fospropofol, a prodrug of propofol in clinical development, can also be targeted to moderate sedation if co‐administered with narcotic.

Conclusion

Moderate sedation provides a safety margin when compared with deep sedation and general anaesthesia. Development of protocols that target agents such as propofol to moderate sedation will expand the sedation agents available to non‐anaesthesiologists and help ensure that this expansion occurs safely.
Oesophageal acid exposure and altered neurocardiac function in patients with GERD and idiopathic cardiac dysrhythmias
Authors: CUOMO R. , DE GIORGI F. , ADINOLFI L. , SARNELLI G. , LOFFREDO F. , EFFICIE E. , VERDE C. , SAVARESE M. F. , USAI P. , BUDILLON G.
Published: June 2006

Background

Oesophageal sensory stimuli alter neurocardiac function through autonomic reflexes.

Aim

To evaluate in patients with idiopathic supraventricular cardiac dysrhythmias and gastro‐oesophageal reflux disease (GERD) whether GE reflux alters neurocardiac function and the effect of acid suppression on cardiac symptoms.

Methods

Thirty‐two patients (13 females and 19 males; age: 20–69 years) with dysrhythmias plus GERD, and nine patients (five females and four males; age: 43–58 years) with GERD only, underwent simultaneous 24‐h pH‐metry and ECG monitoring. Power spectrum analysis of heart rate variability (PSHRV) was obtained with both its low frequency (LF, sympathetic modulation) and high frequency (HF, vagal modulation) components. Hourly mean oesophageal pH and LF/HF ratio were correlated. A 3 months full‐dosage PPI therapy (esomeprazole 40 mg/day) was prescribed.

Results

In 18 (56%) of the 32 patients with dysrhythmia and in none with GERD only, a significant (P < 0.05) correlation between oesophageal pH and LF/HF ratio (oesophagus–heart correlation) was observed. A significant reduction of cardiac symptoms after PPI therapy was observed only in these patients (13/16 vs. 4/11,P < 0.01).

Conclusions

This study has identified a subgroup of dysrhythmic patients in whom the oesophageal acid stimulus elicited cardiac autonomic reflexes. In these patients acid suppression seems to improve GERD and cardiac symptoms.
Cyclophosphamide pulse therapy followed by azathioprine or methotrexate induces long‐term remission in patients with steroid‐refractory Crohn's disease
Authors: SCHMIDT C. , WITTIG B. M. , MOSER C. , ZEITZ M. , STALLMACH A.
Published: June 2006

Background

In patients with steroid‐refractory Crohn's disease, the therapeutic goal is to achieve both rapid remission and maintenance of clinical response.

Aim

To evaluate the long‐term benefit in patients treated with cyclophosphamide pulse therapy and azathioprine or methotrexate, a combination shown to be effective in a recent pilot study.

Methods

Sixteen patients with acute steroid‐refractory Crohn's disease participated in a prospective open‐labelled uncontrolled pilot study between December 1998 and June 2003. All had a median number of 4 monthly pulses of intravenous cyclophosphamide (750 mg) and were followed until relapse of the disease.

Results

Thirteen of 16 patients (81%) achieved remission within 8 weeks after two pulses of cyclophosphamide in combination with azathioprine or methotrexate, with a Crohn's Disease Activity Index decrease from 294 to 111 (median). Remission sustained for 19 months (median, range: 1–45). Moreover, eight patients with pyoderma gangrenosum and erythema nodosum who responded to cyclophosphamide have maintained their remission for up to 30 months.

Conclusions

In steroid refractory patients with Crohn's disease, cyclophosphamide is highly effective to induce remission. This uncontrolled study indicates that cyclophosphamide‐induced remission is long‐lasting under standard immunosuppressive therapy.
Prevalence and management of abdominal cramping and pain: a multinational survey
Authors: QUIGLEY E. M. M. , LOCKE G. R. , MUELLER‐LISSNER S. , PAULO L. G. , TYTGAT G. N. , HELFRICH I. , SCHAEFER E.
Published: June 2006

Background

Though functional gastrointestinal complaints are recognised as being common throughout the world, there have been few comparative studies of prevalence.

Aim

To compare the prevalence and management of abdominal cramping/pain in nine countries.

Methods

In a two‐stage community survey, approximately 1000 subjects were interviewed in each of nine countries to establish the demographics of individuals with abdominal cramping/pain (stage 1) followed by market research‐driven interviews with ≥200 sufferers per country (stage 2).

Results

9042 subjects were interviewed in stage 1. Mexico (46%) and Brazil (43%) had the highest prevalence of abdominal cramping/pain; Japan the lowest (10%). Abdominal cramping/pain was more common in women (12–55%) than in men (7–38%).

About 1717 subjects participated in stage 2; 65% were women and the average age at symptom onset was 29 years. The frequency of episodes differed between countries, being highest in the US (61% suffered at least once in a week). Sufferers in the US and Latin America reported a higher usage of medications (around 90%) than those in Europe (around 72%). In most countries over‐the‐counter drugs were principally used. Antispasmodic drugs were most popular in Latin America and Italy, antacids in Germany and the UK. Drug therapy decreased the duration of episodes (by up to 81% in Brazil).

Conclusions

The community prevalence, severity, healthcare seeking and medication usage related to abdominal cramping/pain are high overall, but vary considerably between countries.
Systematic review: the treatment of anal fissure
Authors: STEELE S. R. , MADOFF R. D.
Published: June 2006

Background

Anal fissure is one of the most common anorectal conditions encountered in clinical practice. Most patients experience anal pain with defecation and minor bright red rectal bleeding, allowing a focused history to direct the evaluation.

Methods

A systematic medical literature search of NIH, Pubmed, and MEDLINE using the search terms anal fissure, sphincterotomy, anal surgery and anal fissure medical therapy. English language was not a restriction. Cited references were used to find additional studies.

Results

No single treatment is the best choice for all patients. Because pharmacological therapy is not associated with permanent alterations in continence, a trial of either a topical sphincter relaxant or botulin toxin injection, along with adequate fluid and fibre intake, is a reasonable option. However, because pharmacological therapy has lower healing and higher relapse rates, surgery can be offered in the first instance to patients without incontinence risk factors who have severe, unrelenting pain and are willing to accept a small risk of incontinence, for the highest likelihood of prompt healing and the lowest risk of recurrence.

Conclusions

Both non‐operative and operative approaches currently exist for the management of anal fissure. Improved non‐surgical therapies may continue to lessen the role of sphincter‐dividing surgery in future.