bluuebunny/crossref_metadata_2025 huggingface dataset:
Sub-chronic psychotomimetic phencyclidine induces deficits in reversal learning and alterations in parvalbumin-immunoreactive expression in the rat
Authors: Abdul-Monim Z. , Neill J. C. , Reynolds G. P.
Published: February 2007

Acute administration of the psychotomimetic phencyclidine (PCP) can mimic some features of schizophrenia, while a repeated treatment regimen of PCP may provide a more effective way to model in animals the enduring cognitive dysfunction observed in many schizophrenic patients. The present study aims to investigate behavioural and neuropathological effects of sub-chronic PCP administration. The cognitive deficit induced by sub-chronic PCP was examined using a previously established operant reversal-learning paradigm. Subsequently, the effect of sub-chronic PCP on parvalbumin-immunoreactive (parvalbumin-IR) neurons was assessed using immunohistochemical techniques. Rats were trained to respond for food in an operant reversal-learning paradigm for approximately 6 weeks, followed by sub-chronic administration of PCP (2mg/kg) or vehicle twice daily for 7 days followed 7 days later by behavioural testing. Six weeks post PCP, brains were analysed using immunohistochemical techniques to determine the size and density of parvalbumin-IR in the frontal cortex and hippocampus. Sub-chronic PCP significantly reduced ( p <0.001) percentage correct responding in the reversal phase relative to the initial phase, an effect that persisted throughout the experimental period (4 weeks). The density of parvalbumin-IR neurons was reduced in the hippocampus, with significant reductions in the dentate gyrus and CA2/3 regions ( p <0.001). There were significant changes in the frontal cortex, with a reduction ( p <0.01) in the M1 (motor area 1) region and increases in the M2 (motor area 2) region and cingulate cortex ( p <0.01- p <0.001). These results parallel findings of profound hippocampal and more subtle cortical deficits of parvalbumin-IR neurons in schizophrenia, and provide evidence to suggest that sub-chronic PCP can induce a lasting cognitive deficit, an effect that may be related to the observed neuronal deficits.
Pharmacological management of acute mania – does current prescribing practice reflect treatment guidelines?
Authors: Streeruwitz A. , Barnes T. R. E. , Fehler J. , Ohlsen R. , Curtis V. A.
Published: February 2007

The records of 70 inpatients with an acute manic episode were audited, to examine the relationship between current prescribing practice, the recommendations of recent clinical guidance and short-term clinical outcomes. Overall, 38 combinations of medication were prescribed. Within the first 24 hours of treatment, monotherapy with a second generation antipsychotic was favoured. At discharge, combination treatment (a mood stabilizer and a second generation antipsychotic) predominated. Early initiation of medication was significantly associated with an earlier clinical decision to discharge. Prescribing was generally in accord with published guidelines. The findings reinforce the value of prescribing surveys in mental health and the need to share understanding of the constraints that may lead to deviation from prescribing guidelines.
Lack of deleterious effects of buspirone on cognition in healthy male volunteers
Authors: Chamberlain Samuel R. , Müller Ulrich , Deakin Julia B. , Corlett Phil R. , Dowson Jonathan , Cardinal Rudolf N. , Aitken Michael R. F. , Robbins Trevor W. , Sahakian Barbara J.
Published: February 2007

Buspirone is a serotonin 5-HT1A receptor agonist licensed for the treatment of anxiety. Other anxiolytic drugs such as benzodiazepines show significant sedative and other unwanted effects on cognition. Studies to date have yet to investigate cognitive effects of buspirone using well-validated computerized tests.

The aim of this study was to assess acute subjective and cognitive effects of buspirone in healthy volunteers.

Sixty healthy male volunteers received 20mg buspirone, 30mg buspirone, or placebo per os in a double-blind parallel groups design (N=20 per group). Subjective ratings (visual analogue scales) were completed at baseline, and at 1.5 and 3.5 hours post-capsule. Cognitive assessment was undertaken between 1.5 and 3.5 hours post-capsule, including tests of memory, executive planning, impulse control, decision making and cognitive flexibility.

The 30mg buspirone group showed significantly higher subjective ratings of contentedness 3.5 hours after capsule relative to placebo. Treatment and placebo groups did not differ significantly on cognitive measures.

In contrast to benzodiazepines, the anxiolytic buspirone appears to lack detectable deleterious effects on cognition when administered acutely at clinically meaningful doses. Future research directions are discussed in relation to acute and chronic studies in neuropsychiatric populations.
Interaction of potato production systems and the environment: a case of waste water irrigation in central Washington
Authors: Wang H. Holly , Tan Tih Koon , Schotzko R. Thomas
Published: February 2007

Potato production and processing are very important activities in the agricultural economy of the Pacific Northwest. Part of the reason for the development of this industry has been the availability of water for both growing and processing. A great amount of water is used in processing potato products, such as frozen French fries, and the waste water is a pollutant because it contains high levels of nitrate and other nutrients. Using this waste water to irrigate the fields can be a suitable disposal method. Field application will reduce potato fertilizer costs, but it can also cause underground water contamination if over-applied to the field. In this econometric study, we used field data associated with current waste water applications in central Washington to examine the yield response as well as the soil nitrogen content response to waste water applications. Our results from the production model show that both water and nitrogen positively affect crop yields at the current levels of application, but potassium has been over applied. This implies that replacing some waste water with fresh water and nitrogen fertilizer will increase production. The environmental model results show that applying more nitrogen to the soil leads to more movement below the root zone. The results also suggest that higher crop yields lead to less nitrogen in the soil, and applying more water increases crop yields, which can reduce the nitrogen left in the soil. Therefore, relative to the current practice, waste water application rates should be reduced and supple-mented with fresh water to enhance nitrogen use by plants and reduce residual nitrogen in the soil.
The controlling of landfill leachate evapotranspiration from soil–plant systems with willow: Salix amygdalina L
Authors: Białowiec Andrzej , Wojnowska-Baryła Irena , Hasso-Agopsowicz Marek
Published: February 2007

The use of willows ( Salix amygdalina L) to manage landfill leachate disposal is an effective and cost-effective method due to the high transpiration ability of the willow plants. A 2-year lysimetric experiment was performed to determine an optimum leachate hydraulic loading rate to achieve high evapotranspiration but exert no harmful influence on the plants. The evapotranspiration rate of a soil–plant system planted with the willow was 1.28–5.12-fold higher than the rate measured on a soil surface lacking vegetation, suggesting that soil– willow systems with high volatilization rates are a viable landfill leachate treatment method. Of the soil–willow systems, the one with willow growing on sand amended with sewage sludge soil at an hydraulic loading rate of 1 mm day-1 performed best, with evapotranspiration ranging from 2.25 to 3.02 mm day-1 and a biomass yield of 8.0–9.85 Mg dry matter ha-1. The organic fraction of the soil increased as much as 2.5% of dry matter, due to the sewage sludge input, which exerted a positive effect on the biomass yield as well as on transpiration and evaporation. It was observed that the plants in the sand-and-sewage sludge soil systems displayed higher resistance to toxic effects from the applied landfill leachate relative to plants in the sand–soil systems.
Microbial C and N dynamics during composting process of urban solid waste
Authors: Ayed Layla Ben , Hassen Abdennaceur , Jedidi Naceur , Saidi Neila , Bouzaiane Olfa , Murano Fumio
Published: February 2007

Microbial characterization of composting is of importance for the optimization of the process and the quality of the end product. The aim of this work was to follow microbial biomass C and N dynamics during the composting process of urban solid waste. Microbial biomass C ( BC) ranged from 4.06 to 1 μg kg-1 of dry compost from day 5 to day 62 and decreased to reach 0.44 mg kg-1 in mature compost. Microbial biomass N ( BN) showed the same trend as BC, ranging from 1.472 to 0.443 μg kg-1 of dry compost from day 5 to day 62. This behaviour is probably related to the decreasing availability of readily decomposable substrates with the ongoing of the process. BC and BN showed a strong correlation ( r = 0.78). The dynamics of the BC/ BN ratio, index of the chemical composition of the whole microbial population suggested a shift in the composition of microbial populations during the process from prevailing bacteria and actinomycetes to prevailing fungi.
Altruism and the Decision to Vote
Authors: Jankowski Richard
Published: February 2007

A core problem at the foundation of rational-actor models for politics is the seeming irrationality of voting, i.e. that it is irrational for voters to vote and to be informed about politics. Myerson has shown that only low turnouts are feasible if we just assume citizens vote on the basis of self interest, and there is uncertainty as to the number of voters. I modify the standard analysis by arguing that individuals are motivated by weak altruistic considerations when deciding whether to vote. First, I present a formal analysis of voting that has a unique, symmetric Bayes–Nash equilibrium for the voting game. It is a mixedstrategy equilibrium which also specifies the conditions under which high turnouts (in excess of 50% of the potential voters) will result. Second, I present an empirical test of the hypothesis using a unique data set (the National Election Survey Pilot Study in 1995) which includes various measures of ‘humanitarianism.’ I am able to integrate that survey with the 1994 NES election survey to provide evidence that weak altruism is the single most important determinant of the decision to vote.
Failure to Return for HIV Test Results: A Pilot Study of Three Community Testing Sites
Authors: Grusky Oscar , Roberts Kathleen Johnston , Swanson Aimee-Noelle
Published: February 2007

Background: Individuals at elevated risk of contracting HIV frequently fail to return for their test result. Because rapid HIV antibody testing is still not widely implemented, failure to return for test results under conditions of standard testing remains a problem.

Methods:Direct field observation and semistructured interviews with clients (N = 16) and test counselors (N = 16) of 3 community HIV testing sites were conducted.

Results: Clients faced 5 barriers to receiving their result: (1) fear, (2) busyness, (3) apathy,(4) inebriation at the time of testing, and (5) testing “on a whim.” Motivators that encouraged clients to receive their results were (1) positive counselor/client interactions, (2) client-friendly policies regarding picking up the test result, (3) clients’ psychological “need to know,” (4) incentives for picking up the result, and (5) established protocols for contacting clients who fail to return.

Conclusion: Findings highlight the need for interventions to improve the return rate for HIV results.
Generic and Branded Drugs for the Treatment of People Living With HIV/AIDS
Authors: Bartlett John A. , Muro Eva P.
Published: February 2007

HIV/AIDS care has benefited tremendously from the availability of antiretroviral (ARV) drugs, both branded and generic. Drug discovery and innovation is the result of direct investment in the development of branded medications, a crucial process for future improvements in care. However, the cost of branded medications is too high for resource-limited countries, where most persons with HIV/AIDS live. Generic drugs dramatically lower the cost of care; however, their safety and efficacy must be ensured and maintained. Proven bioavailability and bioequivalence, in addition to satisfactory manufacturing, distribution, and administration, are keys to successfully implementing the use of qualified generic ARVs. Agencies such as the US Food and Drug Administration (FDA), European Medicines Agency (EMEA), and the World Health Organization (WHO), continue to strengthen the surveillance process through which qualified generic and branded drugs are provided worldwide. Generic drugs have the potential to cause harm if rigorous standards for their use are not followed, but those that are qualified offer great promise in the treatment of HIV/AIDS.
Hsp90 regulates the Fanconi anemia DNA damage response pathway
Authors: Oda Tsukasa , Hayano Toshiya , Miyaso Hidenobu , Takahashi Nobuhiro , Yamashita Takayuki
Published: February 2007

Heat shock protein 90 (Hsp90) regulates diverse signaling pathways. Emerging evidence suggests that Hsp90 inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG), enhance DNA damage-induced cell death, suggesting that Hsp90 may regulate cellular responses to genotoxic stress. However, the underlying mechanisms are poorly understood. Here, we show that the Fanconi anemia (FA) pathway is involved in the Hsp90-mediated regulation of genotoxic stress response. In the FA pathway, assembly of 8 FA proteins including FANCA into a nuclear multiprotein complex, and the complex-dependent activation of FANCD2 are critical events for cellular tolerance against DNA cross-linkers. Hsp90 associates with FANCA, in vivo and in vitro, in a 17-AAG–sensitive manner. Disruption of the FANCA/Hsp90 association by cellular treatment with 17-AAG induces rapid proteasomal degradation and cytoplasmic relocalization of FANCA, leading to impaired activation of FANCD2. Furthermore, 17-AAG promotes DNA cross-linker–induced cytotoxicity, but this effect is much less pronounced in FA pathway-defective cells. Notably, 17-AAG enhances DNA cross-linker–induced chromosome aberrations. In conclusion, our results identify FANCA as a novel client of Hsp90, suggesting that Hsp90 promotes activation of the FA pathway through regulation of intracellular turnover and trafficking of FANCA, which is critical for cellular tolerance against genotoxic stress.
Effector and regulatory T-cell function is differentially regulated by RelB within antigen-presenting cells during GVHD
Authors: MacDonald Kelli P. A. , Kuns Rachel D. , Rowe Vanessa , Morris Edward S. , Banovic Tatjana , Bofinger Helen , O'Sullivan Brendan , Markey Kate A. , Don Alistair L. , Thomas Ranjeny , Hill Geoffrey R.
Published: February 2007

Antigen-presenting cells (APCs) are critical for the initiation of graft-versus-host disease (GVHD), although the responsible APC subset and molecular mechanisms remain unclear. Because dendritic cells (DCs) are the most potent APCs and the NF-kB/Rel family member RelB is associated with DC maturation and potent APC function, we examined their role in GVHD. Within 4 hours of total body irradiation, RelB nuclear translocation was increased and restricted to CD11chi DCs within the host APC compartment. Furthermore, the transient depletion of CD11chi donor DCs that reconstitute in the second week after transplantation resulted in a transient decrease in GVHD severity. By using RelB−/− bone marrow chimeras as transplant recipients or RelB−/− donor bone marrow, we demonstrate that the induction and maintenance of GVHD is critically dependent on this transcription factor within both host and donor APCs. Critically, RelB within APCs was required for the expansion of donor helper T cell type 1 (Th1) effectors and subsequent alloreactivity, but not the peripheral expansion or function of donor FoxP3+ regulatory T cells. These data suggest that the targeted inhibition of nuclear RelB translocation within APCs represents an attractive therapeutic strategy to dissociate effector and regulatory T-cell function in settings of Th1-mediated tissue injury.
Ongoing research in Europe: Alpha One International Registry (AIR) objectives and development
Authors: Stockley R. A. , Luisetti M. , Miravitlles M. , Piitulainen E. , Fernandez P.
Published: February 2007

In 1997, the World Health Organization recommended establishing an international registry of α1-antitrypsin deficiency. The objective of the present article is to describe the organisation of an international network of registries, the Alpha One International Registry (AIR), and the processes of enrolling and entering data.

By the end of 2005, the registry included individuals from 21 countries (from four continents). The inclusion criterion was either phenotypes PiZZ, PiSZ or other severely deficient variants. Demographic and clinical information have been collected by a standardised questionnaire, translated for each country. Data are transferred to the AIR database at the Dept of Respiratory Medicine, University Hospital, Malmö, Sweden, either by e-mail orviatwo web-enabled questionnaires in HTML. All data are merged and checked for consistency and missing values.

Collection of data started in 1999 and, by September 2005, data on 2,150 individual patients (1,180 male) had been submitted. Of these, 1,855 (84%) have phenotype PiZ, 181 (8%) PiSZ and 114 (5%) other rare Pi phenotypes. The mean age at inclusion was 49.8 yrs (sd = 13.3) and the majority were index cases (64.1%).

The Alpha One International Registry is the largest specific α1-antitrypsin deficiency registry, fulfilling a major World Health Organization recommendation. The success related to the convergence of national registries into a common database creating a unique registry beyond geographic boundaries and encompassing α1-antitrypsin deficiency from various ethnic groups.
Carbapenems for the treatment of immunocompetent adult patients with nosocomial pneumonia
Authors: Siempos I. I. , Vardakas K. Z. , Manta K. G. , Falagas M. E.
Published: February 2007

The comparative effectiveness and safety of carbapenems with other β-lactams and fluoroquinolones for the empirical treatment of patients with hospital-acquired pneumonia remains controversial.

In the present study, a meta-analysis of 12 relevant randomised controlled trials was performed.

Overall, carbapenems were associated with lower mortality than fluoroquinolones or β-lactams, alone or in combination with aminoglycosides (odds ratio 0.72, 95% confidence interval 0.55–0.95). There was no difference between the compared antibiotics regarding treatment success (1.08, 0.91–1.29), microbiological success (1.04, 0.72–1.50) or development of adverse effects (0.81, 0.46–1.43). In the subset of patients withPseudomonas aeruginosapneumonia, carbapenems were associated with lower treatment success (0.42, 0.22–0.82) and lower eradication ofP.strains (0.50, 0.24–0.89).

Carbapenems are equivalent to fluoroquinolones or β-lactams, alone or in combination with aminoglycosides, for the empirical treatment of immunocompetent adult patients with hospital-acquired pneumonia. However, there is limited evidence, based predominantly on unblinded randomised controlled trials, that carbapenems are associated with lower mortality than the comparators; this association was not observed in a subset analysis of randomised controlled trials with a high methodological quality score. In patients withPseudomonas aeruginosapneumonia, carbapenems are associated with worse outcomes than the comparators.
Scientific rationale for using a single inhaler for asthma control
Authors: Barnes P. J.
Published: February 2007

Clinical trials have recently demonstrated that using a budesonide/formoterol combination inhaler as regular maintenance treatment twice daily but also as a rescue therapy for breakthrough symptoms can provide more effective control of asthma, particularly in reducing exacerbations, than using a short-acting β2-agonist or formoterol as rescue therapy. This suggests that the corticosteroid component of the combination therapy plays an important role in rescue therapy.

Formoterol as a rescue therapy is effective in relieving symptoms by relaxing airway smooth muscle but is also likely to have important inhibitory effects on mast cells, plasma exudation and neutrophilic inflammation.

Inhaled corticosteroids have much more rapid suppressing effects on airway inflammation than previously recognised and the increased dose used as rescue therapy may prevent the increase in airway inflammation that occurs during the evolution of an exacerbation, thus preventing its development.

It is likely that the molecular interactions between β2-agonists and corticosteroids also enhance the effect of the combination therapy as rescue therapy. There is now a strong scientific rationale for single inhaler therapy in asthma, but more research is now needed to better understand the mechanisms involved.
Tobacco use in relation to COPD and asthma: Fig. 1—
Authors: Hylkema M. N. , Sterk P. J. , de Boer W. I. , Postma D. S.
Published: February 2007

Smoking is the leading cause of preventable death worldwide. Hundreds of millions of individuals still smoke, affecting their health as well as that of their peers, family and offspring. Smoking is a well-established prime risk factor for chronic obstructive pulmonary disease and hampers the response to treatment in asthma and chronic obstructive pulmonary disease. In the present paper, new concepts are discussed with respect to pathology, treatment, smoking cessation and tobacco control. Recommendations for future directions are given.
Formation of multinucleated giant cells and microglial degeneration in rats expressing a mutant Cu/Zn superoxide dismutase gene
Authors: Fendrick Sarah E , Xue Qing-Shan , Streit Wolfgang J
Published: February 2007

Background

Microglial neuroinflammation is thought to play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS). The purpose of this study was to provide a histopathological evaluation of the microglial neuroinflammatory response in a rodent model of ALS, the SOD1G93A transgenic rat.

Methods

Multiple levels of the CNS from spinal cord to cerebral cortex were studied in SOD1G93A transgenic rats during three stages of natural disease progression, including presymptomatic, early symptomatic (onset), and late symptomatic (end stage), using immuno- and lectin histochemical markers for microglia, such as OX-42, OX-6, and Griffonia simplicifolia isolectin B4.

Results

Our studies revealed abnormal aggregates of microglia forming in the spinal cord as early as the presymptomatic stage. During the symptomatic stages there was prominent formation of multinucleated giant cells through fusion of microglial cells in the spinal cord, brainstem, and red nucleus of the midbrain. Other brain regions, including substantia nigra, cranial nerve nuclei, hippocampus and cortex showed normal appearing microglia. In animals during end stage disease at 4–5 months of age virtually all microglia in the spinal cord gray matter showed extensive fragmentation of their cytoplasm (cytorrhexis), indicative of widespread microglial degeneration. Few microglia exhibiting nuclear fragmentation (karyorrhexis) indicative of apoptosis were identified at any stage.

Conclusion

The current findings demonstrate the occurrence of severe abnormalities in microglia, such as cell fusions and cytorrhexis, which may be the result of expression of mutant SOD1 in these cells. The microglial changes observed are different from those that accompany normal microglial activation, and they demonstrate that aberrant activation and degeneration of microglia is part of the pathogenesis of motor neuron disease.
Which antipsychotics would mental health professionals take themselves?
Authors: Bleakley Stephen , Olofinjana Olubanke , Taylor David
Published: February 2007

Aims and Method

Many studies report prescribing preferences for antipsychotics but few have examined what professionals would choose for themselves if they were diagnosed with schizophrenia. We asked 188 nurses, pharmacists and doctors which antipsychotic they would prefer to be prescribed.

Results

Risperidone (n=49, 26.1%), olanzapine (n=49, 26.1%) and aripiprazole (n=35, 18.6%) were the most popular choices.

Clinical Implications

Professionals' choice was in line with the latest evidence on comparative effectiveness of atypical antipsychotics and therefore might be a sensitive indicator of the most effective antipsychotic.
VAMP4 cycles from the cell surface to the trans-Golgi network via sorting and recycling endosomes
Authors: Tran Ton Hoai Thi , Zeng Qi , Hong Wanjin
Published: February 2007

VAMP4 is enriched in the trans-Golgi network (TGN) and functions in traffic from the early and recycling endosomes to the TGN, but its trafficking itinerary is unknown. Cells stably expressing TGN-enriched VAMP4 C-terminally-tagged with EGFP (VAMP4-EGFP) are able to internalize and transport EGFP antibody efficiently to the TGN, suggesting that VAMP4-EGFP cycles between the cell surface and the TGN. The N-terminal extension of VAMP4 endows a chimeric VAMP5 with the ability to cycle from the surface to the TGN. Detailed time-course analysis of EGFP antibody transport to the TGN as well as pharmacological and thermal perturbation experiments suggest that VAMP4-EGFP is endocytosed by clathrin-dependent pathways and is delivered to the sorting and then recycling endosomes. This is followed by a direct transport to the TGN, without going through the late endosome. The di-Leu motif of the TGN-targeting signal is important for internalization, whereas the acidic cluster is crucial for efficient delivery of internalized antibody from the endosome to the TGN. These results suggest that the TGN-targeting signal of VAMP4 mediates the efficient recycling of VAMP4 from the cell surface to the TGN via the sorting and recycling endosomes, thus conferring steady-state enrichment of VAMP4 at the TGN.
Influence of autophagy genes on ion-channel-dependent neuronal degeneration in Caenorhabditis elegans
Authors: Tóth Márton L. , Simon Péter , Kovács Attila L. , Vellai Tibor
Published: February 2007

Necrotic cell death is a common feature in numerous human neurodegenerative disorders. In the nematode Caenorhabditis elegans, gain-of-function mutations in genes that encode specific ion channel subunits such as the degenerins DEG-1 and MEC-4, and the acetylcholine receptor subunit DEG-3 lead to necrotic-like degeneration of a subset of neurons. Neuronal demise caused by ion channel hyperactivity is accompanied by intense degradation of cytoplasmic contents, dramatic membrane infolding and vacuole formation; however, the cellular pathways underlying such processes remain largely unknown. Here we show that the function of three autophagy genes, whose yeast and mammalian orthologs are implicated in cytoplasmic self-degradation, membrane trafficking and the cellular response to starvation, contributes to ion-channel-dependent neurotoxicity in C. elegans. Inactivation of unc-51, bec-1 and lgg-1, the worm counterparts of the yeast autophagy genes Atg1, Atg6 and Atg8 respectively, partially suppresses degeneration of neurons with toxic ion channel variants. We also demonstrate that the TOR-kinase-mediated signaling pathway, a nutrient sensing system that downregulates the autophagy gene cascade, protects neurons from undergoing necrotic cell death, whereas nutrient deprivation promotes necrosis. Our findings reveal a role for autophagy genes in neuronal cell loss in C. elegans.
Simulation and experimental research on a mixed pulse converter turbocharging system
Authors: Yang Shiyou , Deng Kangyao , Cui Yi
Published: February 2007

A newly developed turbocharging system, called a mixed pulse converter (MIXPC), is proposed and the performance of the proposed system applied to diesel engines is evaluated. The aim of this proposed system is to reduce the scavenging interference between cylinders, and to lower the pumping loss in cylinders and the brake specific fuel consumption (BSFC). In addition, exhaust manifolds of simplified design can be constructed with small dimensions, low weight, and a single turbine entry. An engine performance simulation code, in which a second-order finite volume method + total variation diminishing method is used to simulate the one-dimensional unsteady gas dynamic phenomenon in intake and exhaust pipe systems, has been developed. By simulating a locomotive diesel engine using the module pulse converter (MPC) turbocharging system and the MIXPC, it is found that not only is the average scavenging coefficient of the MIXPC larger than that of the MPC, but also cylinders of the MIXPC have more homogeneous scavenging coefficients than those of the MPC, and the pumping loss and BSFC of the MIXPC are lower than those of the MPC. To validate the prediction results, experiments on a locomotive diesel engine equipped with a MIXPC have been successfully completed. Experimental results show that the MIXPC turbocharging system reduces the exhaust gas temperature before turbine by 80°C and BSFC at part load by 4.3 g/kW h, and the exhaust gas temperatures at each cylinder outlet at high load are more uniform. The diesel engine equipped with the MIXPC has the potential to increase its power to 115 per cent load.
An ultrasonic sound speed sensor for measuring exhaust gas recirculation levels
Authors: Olfert J S , Checkel M D
Published: February 2007

Exhaust gas recirculation (EGR) has been used for years to improve the performance of internal combustion engines. This paper shows that acoustic methods can be used to measure EGR. Theory is presented which shows that measurements of the speed of sound can be used to measure the amount of EGR in the intake manifold. In particular, a new method called the discrete acoustic wave and phase detection (DAWPD) method can be used to measure EGR levels with a fast-response time. Experimental results show that a DAWPD sensor can be used to measure EGR levels with adequate accuracy (± 1.3 per cent EGR) at steady state. Transient measurements were not possible owing to engine limitations. The sensor's performance was limited by the ultrasonic transducers used. It is postulated that sensor performance could be improved with smaller and temperature-independent non-resonant transducers.
Performance and emission characteristics of a gas to liquid fuelled engine
Authors: Lee Seang-wock , Kim Jong-choon , Ryu Jeong-ho , Uhm Dong-seop , Kim Jung-min
Published: February 2007

The objective of the study is, through investigation of visualization and an engine test, to pursue a lower emission engine using GTL (gas to liquid) while maintaining thermal efficiency and fuel consumption. A sulphur-free (<13 ppm) diesel fuel was used as the reference fuel, and the characteristics of the GTL diesel fuel were investigated. As a physical property, the GTL fuel has approximately the same cetane value as the diesel but has low values of PAHs (polycyclic aromatic hydrocarbons), boiling point, density, viscosity, and surface tension. In visualization of spray and combustion, images were taken using a high-speed video camera and analysed by their penetration and evaporation characteristics in comparison with current diesel fuel. Also, in an engine test, a heavy-duty diesel engine which has six-cylinder 11.15 litre displacements was used to test the performance. The results showed that mixture formation of the GTL fuel is faster than that of diesel fuel, depending on the physical properties. In the engine test, a considerable reduction in PM (particulate matter) emission was observed, due to the enhanced fuel atomization and air entrainment, and a reduction in NO x emission can be achieved without deteriorating b.s.f.c. (brake specific fuel consumption).
Analysis of the dynamic performances of a piston-crankshaft system considering oil-film forces reconstructed by a neural network
Authors: Meng F M , Hu Y Z , Wang H , Zhang Y Y
Published: February 2007

A dynamic modelling method for the piston-crankshaft system in an internal combustion engine, including two-dimensional oil-film forces of the piston pack, was proposed. In order to obtain the dynamic performance of this system, the dynamic equations for the components in the system were presented. Meanwhile, a radial base function neural network technology was employed to reconstruct the two-dimensional oil-film forces, which are then coupled to the presented dynamic equations for the components. The validity of the proposed modelling method for the piston-crankshaft system was demonstrated, and conclusions concerning the dynamic performance of the system were drawn.
Mathematical modelling of a vehicle crash with emphasis on the dynamic response analysis of extendable cubic nonlinear dampers using the incremental harmonic balance method
Authors: Elmarakbi A , Zu J
Published: February 2007

A new direction of crashworthiness improvement using a smart extendable front-end structure is introduced in this paper to support the function of the existing vehicle structure. The smart front-end structure consists of two extendable, independently controlled hydraulic cylinders (dampers) integrated with the front-end longitudinal members. The main objectives of the smart front-end structure are to find solutions of the trade-off problem faced by the designer for offset collision events and to mitigate full frontal collisions. The work carried out in this paper includes developing and analysing mathematical models of different vehicle crash scenarios, including vehicle-to-vehicle frontal collision in both full and offset events. In these models, vehicle components are modelled by lumped masses and cubic non-linear springs. The hydraulic cylinders are represented by cubic non-linear damper elements. In this paper, the dynamic responses of the crash events are obtained with the aid of an analytical approach using the incremental harmonic balance method. The intrusion injury as the maximum deformation of the front-end structure and the occupant deceleration injury are used for interpreting the results. It is demonstrated from simulation results that significant improvements to both intrusion and deceleration injuries are obtained using the smart front-end structures.
The development of a dynamometer for torque measurement of automotive turbocharger turbines
Authors: Szymko S , McGlashan N R , Martinez-Botas R , Pullen K R
Published: February 2007

This paper describes the development of a high-power high-speed eddy current dynamometer for turbocharger turbine research. Turbochargers are present in virtually all automotive diesel engines and it is essential to determine the characteristics of the turbine and compressor for inclusion into the engine model. Accurate measurement of the turbocharger turbine torque forms a vital part of this process. Earlier developments of dynamometers for this purpose are summarized and their limitations commented upon. The paper then describes the principle behind a new permanent magnet disc-type eddy current dynamometer including the relevant electromagnetic theory and analysis. The overall performance is given together with the results of an uncertainly analysis; a wide load range of 1.7-62.2 kW has been demonstrated at 60 000 r/min, and it allows characterization of turbine performance over the entire operating range, including the ability to measure unsteady torque.
An instrument for measurement of water contamination in hydraulic fluids
Authors: Owens E H , Smith G H , Reading I A
Published: February 2007

This paper describes an optical instrument that uses the transmission and scattering properties of water droplets in hydraulic fluids to measure the water fraction in the fluid. The instrument consists of a small optical chamber that can be built into an active hydraulic system. Light is supplied via a near-infrared light-emitting diode and is collected via a simple system of lenses and two wavelength-matched detectors placed at 90° to the beam path and directly in the path of the transmitted light. A novel method of measuring the water contamination is utilized that greatly reduces the signal noise caused by dynamic changes in the system during operation.
Optimal turn-back manoeuvre after engine failure in a single-engine aircraft during climb-out
Authors: Brinkman K , Visser H G
Published: February 2007

When a single-engine aircraft suffers an engine failure shortly after take-off, the pilot is forced to execute a power-off glide to a landing. If the engine failure occurs at a low altitude, there is no choice but to land straight ahead. However, when the engine failure occurs at a higher altitude, the possibility arises to turn the aircraft back to the runway. The latter option has the potential to improve survivability, in particular, when the surrounding terrain turns out to be inhospitable. The goal of the present study is to establish under what conditions returning to the runway is a feasible and safe option. To this end, the turn-back landing problem is formulated as an optimal control problem and solved numerically using the direct optimization technique of collocation and non-linear programming. The aircraft model employed in the numerical examples concerns an F-16 fighter aircraft, modelled as a point mass. The influence of wind on the optimal turn-back manoeuvre is also discussed.
Three-axis attitude control using combined gravity-gradient and solar pressure
Authors: Circi C
Published: February 2007

An attitude satellite controller that combines passive gravity-gradient torque with solar pressure torque is proposed for three-axis stabilization of a micro-satellite. A dumbbell satellite configuration is chosen to increase the gravity-gradient torque and a three-axis stabilization is pursued with the help of small solar sails. Solar pressure task is to help the gravity-gradient torque and not to oppose it. The proposed controller is applied to different test cases: first, for satellite stabilization during the tumble motion, due to a nonperfect separation manoeuvre from the launcher last stage; second, the attitude control performances are studied for different eccentric orbits. The results are given in terms of settling time and maximum amplitude oscillations.
High integrity real-time software
Authors: Allerton D J
Published: February 2007

This paper reviews the techniques and issues in developing high integrity real-time software in the aerospace industry. It explains the methods used to achieve high levels of reliability by deploying fault-tolerant hardware architectures. The aspects of software design and programming languages, which influence the safety of software, are introduced. The paper also outlines the need to verify the performance of real-time software. The major part of the paper focuses on the methods used in the certification of software for safety critical applications, covering software development methods used on large programmes. The standard DO-178B has been widely adopted for the certification of software for civil applications in the aerospace industry and the impact of this standard on software development methods for civil aircraft is summarized. The paper concludes with a review of future trends in software development, particularly the use of automatic code generation methods and schematic capture in the software design phase.
Validation of a software tool for optimizing the design of low noise, high strength gears
Authors: Haigh J , Hofmann D A , Bicker R
Published: February 2007

It is now possible to carry out very accurate elastic mesh analysis in order to calculate the variation in elastic mesh deflection as gears go through a meshing cycle. The software, DU-GATES, combines finite-element analysis of a gear tooth and body with an analytical elastic mesh model, enabling very fast elastic mesh analysis and effective optimization of gear macro-and microgeometry for minimum transmission error and stress. Unlike other elastic mesh models, the software has been exhaustively validated on a large-scale 8 MW gear research rig. This article outlines the capabilities of this procedure in the testing of gears by way of correlation between predicted and measured dynamic excitation, which manifests itself in the form of gear noise.
Development of the technical capabilities needed to build and position a prepolarization coil for a magnetic resonance imaging magnet
Authors: Jaensch M , Young I R , Besant C , Atkins A , Lamperth M
Published: February 2007

An experiment to show that a magnetic resonance imaging (MRI) magnet could be assembled around a patient, and used as part of a prepolarization system in which substantial transient forces are applied to parts of it, is described. The paper describes the circumstances that develop as a result of the application of the large transient fields used in this type of study, and outlines the reason for the tolerances that are permissible on the alignment of the system components. It then describes a test rig used to evaluate how the various problems might be overcome, and reports on the performance achieved with this rig. On the basis of this work, it appears that a system could be developed that would allow the application of these methods in clinical MRI.
Physical properties of ultrafast deposited micro- and nanothickness amorphous hydrogenated carbon films for medical devices and prostheses
Authors: Zaharia T , Sullivan J L , Saied S O , Bosch R C , Bijker M D
Published: February 2007

Hydrogenated amorphous carbon films with diamond-like structures have been formed on different substrates at very low energies and temperatures by a plasma-enhanced chemical vapour deposition (PECVD) process employing acetylene as the precursor gas. The plasma source was of a cascaded arc type with argon as the carrier gas. The films grown at very high deposition rates were found to have a practical thickness limit of ∼1.5 μm, above which delamination from the substrate occurred. Deposition on silicon (100), glass, and plastic substrates has been studied and the films characterized in terms of sp3 content, roughness, hardness, adhesion, and optical properties. Deposition rates of up to 20 nm/s have been achieved at substrate temperatures below 100 °C. A typical sp3 content of 60-75 per cent in the films was determined by X-ray-generated Auger electron spectroscopy (XAES). The hardness, reduced modulus, and adhesion of the films were measured using a MicroMaterials NanoTest indenter/scratch tester. Hardness was found to vary from 4 to 13 GPa depending on the admixed acetylene flow and substrate temperature. The adhesion of the film to the substrate was significantly influenced by the substrate temperature and whether an in situ d.c. cleaning was employed prior to the deposition process. The hydrogen content in the film was measured by a combination of the Fourier transformation infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. From the results it is concluded that the films formed by the process described here are ideal for the coating of long-term implantable medical devices, such as prostheses, stents, invasive probes, catheters, biosensors, etc. The properties reported in this publication are comparable with good-quality films deposited by other PECVD methods. The advantages of these films are the low ion energy and temperature of deposition, ensuring that no damage is done to sensitive substrates, very high deposition rates, relatively low capital cost of the equipment required, and the ease of adjustment of plasma parameters, which facilitates film properties to be tailored according to the desired application.
Force measurement and mechanical characterization of living Drosophila embryos for human medical study
Authors: Shen Y , Wejinya U C , Xi N , Pomeroy C A
Published: February 2007

The objective of this paper is to investigate and characterize the force behaviour and mechanical properties of living Drosophila embryos using an in situ polyvinylidene fluoride (PVDF) piezoelectric microforce-sensing tool with a resolution in the range of submicro newtons. The Drosophila embryo is one of the most studied organisms in biological research, medical research, genetics, and developmental biology and has implications in the cure of human diseases. It is also used to study the wiring of the human brain and the nervous system. For a highly efficient and accurate microinjection of genetic material into a Drosophila embryo, it is absolutely necessary to allow close monitoring of the magnitude and direction of microinjection and other biomanipulation forces acting on the embryo during the injection process. In this paper, a networked microrobotic biomanipulation platform integrating a twoaxis (two-dimensional) PVDF microforce-sensing tool is used to implement force sensing and injection of living Drosophila embryos. Based on the event synchronization for the feedback of injection video and microforce, the developed networked microrobotic platform can greatly advance operations in microinjection and biomanipulation. Through experiments, quantitative relationships between the applied force and membrane structural deformation of embryos in different stages of embryogenesis and their microinjection force behaviours were investigated. Ultimately, the technology will provide a critical and major step towards the development of automated biomanipulation for batch injection of living embryos in genetic and developmental studies, which will facilitate the development of medicine for the cure of human diseases.
Short-fibre reinforcement of calcium phosphate bone cement
Authors: Buchanan F , Gallagher L , Jack V , Dunne N
Published: February 2007

Calcium phosphate cement (CPC) sets to form hydroxyapatite, a major component of mineral bone, and is gaining increasing interest in bone repair applications. However, concerns regarding its brittleness and tendency to fragment have limited its widespread use. In the present study, short-fibre reinforcement of an apatitic calcium phosphate has been investigated to improve the fracture behaviour. The fibres used were polypropylene (PP) fibres, 50 μm in diameter and reduced in length by cryogenic grinding. The compressive strength and fracture behaviour were examined. Fibre addition of up to 10 wt% had a significant effect on composite properties, with the energy absorbed during failure being significantly increased, although this tended to be accompanied with a slight drop in compressive strength. The fibre reinforcement mechanisms appeared to be crack bridging and fibre pull-out. The setting time of the CPC with fibre reinforcement was also investigated and was found to increase with fibre volume fraction.
Use of fuchsine basic: Ethylenediaminetetraacetic acid system in photogalvanic cell for solar energy conversion
Authors: Madhwani S , Vardia J , Punjabi P. B. , Sharma V. K.
Published: February 2007

Fuchsine basic has been used as a photosensitizer in photogalvanic cell for solar energy conversion. Ethylenedianinetetraacetic acid was used as an electron donor. The photopotential and photocurrent generated by this cell were 650.0 mV and 60.0 μA, respectively. The effects of various parameters, such as pH, light intensity, diffusion length, reductant concentration, dye concentration, etc. on the electrical output of the cell has been studied. The current-voltage ( i-V) characteristics of the cell have also been observed, and a tentative mechanism for the generation of photocurrent has been proposed. Performance of the cell was determined in dark at its power point.