Effects of ethanol on combustion and emissions of a gasoline engine operating with different combustion modes

The introduction of fuel economy and CO2 emission legislations for passenger cars in many countries and regions has spurred the research and development of more efficient gasoline engines. The pumping loss at part-load operations is a major factor for the higher fuel consumption of spark ignition (SI) gasoline engines than the diesel engines. Various approaches have been identified to reduce the pumping loss at part-load operations, leading to improved fuel economy, including Early Intake Valve Closing (EIVC), Positive Valve Overlap (PVO) and Controlled Auto-Ignition (CAI) combustion. On the other hand, in order to reduce the CO2 emissions from the fossil fuel, ethanol produced from renewable resources is becoming widely used in the gasoline engine. In this paper, the performance, combustion and emissions were measured, analyzed and compared between gasoline and its mixture with ethanol (E15 and E85) at a typical part-load condition when a direct injection gasoline engine was operated with the CAI combustion by means of the negative valve overlap (NVO) and SI combustion by means of the intake throttled, EIVC and PVO. An electro hydraulic actuated camless system enabled the engine to be operated with CAI combustion and SI combustion of different valve timings and durations at the same load. The results showed that the CAI combustion reduces NOx emissions by more than 90%. The PVO results in better mixture preparations and improved combustion efficiency and best fuel economy compared to all the other modes. The EIVC operation led to a moderate improvement in the fuel conversion efficiency over the throttled SI operation but it was characterised by the slowest combustion and worst HC and CO emissions. Fewer and smaller particles numbers were detected in EIVC using E0 and E15 fuel blends. Using ethanol blends reduces the knocking combustion in CAI modes by about 50%. The use of E85 resulted in an increased number of particulate emissions in EIVC but increased ISFC in all the modes. The particulate emission results showed that soot is the dominant particle in the exhaust

The Energy Landscape, Folding Pathways and the Kinetics of a Knotted Protein

The folding pathway and rate coefficients of the folding of a knotted protein are calculated for a potential energy function with minimal energetic frustration. A kinetic transition network is constructed using the discrete path sampling approach, and the resulting potential energy surface is visualized by constructing disconnectivity graphs. Owing to topological constraints, the low-lying portion of the landscape consists of three distinct regions, corresponding to the native knotted state and to configurations where either the N- or C-terminus is not yet folded into the knot. The fastest folding pathways from denatured states exhibit early formation of the N-terminus portion of the knot and a rate-determining step where the C-terminus is incorporated. The low-lying minima with the N-terminus knotted and the C-terminus free therefore constitute an off-pathway intermediate for this model. The insertion of both the N- and C-termini into the knot occur late in the folding process, creating large energy barriers that are the rate limiting steps in the folding process. When compared to other protein folding proteins of a similar length, this system folds over six orders of magnitude more slowly.Comment: 19 page

Neural correlates of enhanced visual short-term memory for angry faces: An fMRI study

Copyright: © 2008 Jackson et al.Background: Fluid and effective social communication requires that both face identity and emotional expression information are encoded and maintained in visual short-term memory (VSTM) to enable a coherent, ongoing picture of the world and its players. This appears to be of particular evolutionary importance when confronted with potentially threatening displays of emotion - previous research has shown better VSTM for angry versus happy or neutral face identities.Methodology/Principal Findings: Using functional magnetic resonance imaging, here we investigated the neural correlates of this angry face benefit in VSTM. Participants were shown between one and four to-be-remembered angry, happy, or neutral faces, and after a short retention delay they stated whether a single probe face had been present or not in the previous display. All faces in any one display expressed the same emotion, and the task required memory for face identity. We find enhanced VSTM for angry face identities and describe the right hemisphere brain network underpinning this effect, which involves the globus pallidus, superior temporal sulcus, and frontal lobe. Increased activity in the globus pallidus was significantly correlated with the angry benefit in VSTM. Areas modulated by emotion were distinct from those modulated by memory load.Conclusions/Significance: Our results provide evidence for a key role of the basal ganglia as an interface between emotion and cognition, supported by a frontal, temporal, and occipital network.The authors were supported by a Wellcome Trust grant (grant number 077185/Z/05/Z) and by BBSRC (UK) grant BBS/B/16178

Protective effects of a gastrointestinal agent containing Korean red ginseng on gastric ulcer models in mice

<p>Abstract</p> <p>Background</p> <p>Korean red ginseng (KRG) is a ginseng that has been cultivated and aged for 4-6 years or more, and goes through an extensive cleaning, steaming and drying process. KRG contains more than 30 kinds of saponin components and has been reported as having various biological properties, such as anti-fatigue action, immune restoration, and neurovegetative effect. The purpose of this study was to assess the effects of a KRG-containing drug (KRGCD) on gastric ulcer models in mice.</p> <p>Methods</p> <p>Stomach ulcers were induced by oral ingestion of hydrochloride (HCl)/ethanol or indomethacin. Treatment with KRGCD (30, 100, and 300 mg/kg, p.o.) occurred 1 hr before the ulcer induction. Effect of KRGCD on anti-oxidant activity and gastric mucosal blood flow with a laser Doppler flowmeter in mice stomach tissue was evaluated.</p> <p>Results</p> <p>KRGCD (100 and 300 mg/kg, p.o.) significantly decreased ethanol- and indomethacin-induced gastric ulcer compared with the vehicle-treated (control) group. KRGCD (100 and 300 mg/kg) also decreased the level of thiobarbituric acid reactive substance (TBARS) and increased gastric mucosal blood flow compared with the control group.</p> <p>Conclusions</p> <p>These results suggest that the gastroprotective effects of KRGCD on mice ulcer models can be attributed to its ameliorating effect on oxidative damage and improving effect of gastric mucosal blood flow.</p

Socio-demographic and AIDS-related factors associated with tuberculosis stigma in southern Thailand: a quantitative, cross-sectional study of stigma among patients with TB and healthy community members

<p>Abstract</p> <p>Background</p> <p>Tuberculosis (TB) remains one of the most important infectious diseases worldwide. A comprehensive approach towards disease control that addresses social factors including stigma is now advocated. Patients with TB report fears of isolation and rejection that may lead to delays in seeking care and could affect treatment adherence. Qualitative studies have identified socio-demographic, TB knowledge, and clinical determinants of TB stigma, but only one prior study has quantified these associations using formally developed and validated stigma scales. The purpose of this study was to measure TB stigma and identify factors associated with TB stigma among patients and healthy community members.</p> <p>Methods</p> <p>A cross-sectional study was performed in southern Thailand among two different groups of participants: 480 patients with TB and 300 healthy community members. Data were collected on socio-demographic characteristics, TB knowledge, and clinical factors. Scales measuring perceived TB stigma, experienced/felt TB stigma, and perceived AIDS stigma were administered to patients with TB. Community members responded to a community TB stigma and community AIDS stigma scale, which contained the same items as the perceived stigma scales given to patients. Stigma scores could range from zero to 30, 33, or 36 depending on the scale. Three separate multivariable linear regressions were performed among patients with TB (perceived and experience/felt stigma) and community members (community stigma) to determine which factors were associated with higher mean TB stigma scores.</p> <p>Results</p> <p>Only low level of education, belief that TB increases the chance of getting AIDS, and AIDS stigma were associated with higher TB stigma scores in all three analyses. Co-infection with HIV was associated with higher TB stigma among patients. All differences in mean stigma scores between index and referent levels of each factor were less than two points, except for incorrectly believing that TB increases the chance of getting AIDS (mean difference of 2.16; 95% CI: 1.38, 2.94) and knowing someone who died from TB (mean difference of 2.59; 95% CI: 0.96, 4.22).</p> <p>Conclusion</p> <p>These results suggest that approaches addressing the dual TB/HIV epidemic may be needed to combat TB stigma and that simply correcting misconceptions about TB may have limited effects.</p

Characterisation and Carriage Ratio of Clostridium difficile Strains Isolated from a Community-Dwelling Elderly Population in the United Kingdom

Background Community-associated Clostridium difficile infection (CDI) appears to be an increasing problem. Reported carriage rates by C.difficile are debatable with suggestions that primary asymptomatic carriage is associated with decreased risk of subsequent diarrhoea. However, knowledge of potential reservoirs and intestinal carriage rates in the community, particularly in the elderly, the most susceptible group, is limited. We have determined the presence of C.difficile in the faeces of a healthy elderly cohort living outside of long-term care facilities (LCFs) in the United Kingdom. Methods Faecal samples from 149 community-based healthy elderly volunteers (median age 81 years) were screened for C.difficile using direct (Brazier's CCEY) and enrichment (Cooked Meat broth) culture methods and a glutamate dehydrogenase (GDH) immunoassay. Isolates were PCR-ribotyped and analysed for toxin production and the presence of toxin genes. Results Of 149 faecal samples submitted, six (4%) were found to contain C.difficile. One particular sample was positive by both the GDH immunoassay and direct culture, and concurrently produced two distinct strain types: one toxigenic and the other non-toxigenic. The other five samples were only positive by enrichment culture method. Overall, four C.difficile isolates were non-toxigenic (PCR-ribotypes 009, 026 (n = 2) and 039), while three were toxigenic (PCR-ribotypes 003, 005 and 106). All individuals who had a positive culture were symptom-free and none of them had a history of CDI and/or antibiotics use in the 3 month period preceding recruitment. Conclusions To our knowledge, this is the first study of the presence of C.difficile in healthy elderly community-dwelling individuals residing outside of LCFs. The observed carriage rate is lower than that reported for individuals in LCFs and interestingly no individual carried the common epidemic strain PCR-ribotype 027 (NAP1/BI). Further follow-up of asymptomatic carriers in the community, is required to evaluate host susceptibility to CDI and identify dynamic changes in the host and microbial environment that are associated with pathogenicity

Neural Circuitry of Emotional and Cognitive Conflict Revealed through Facial Expressions

Neural systems underlying conflict processing have been well studied in the cognitive realm, but the extent to which these overlap with those underlying emotional conflict processing remains unclear. A novel adaptation of the AX Continuous Performance Task (AX-CPT), a stimulus-response incompatibility paradigm, was examined that permits close comparison of emotional and cognitive conflict conditions, through the use of affectively-valenced facial expressions as the response modality.Brain activity was monitored with functional magnetic resonance imaging (fMRI) during performance of the emotional AX-CPT. Emotional conflict was manipulated on a trial-by-trial basis, by requiring contextually pre-cued facial expressions to emotional probe stimuli (IAPS images) that were either affectively compatible (low-conflict) or incompatible (high-conflict). The emotion condition was contrasted against a matched cognitive condition that was identical in all respects, except that probe stimuli were emotionally neutral. Components of the brain cognitive control network, including dorsal anterior cingulate cortex (ACC) and lateral prefrontal cortex (PFC), showed conflict-related activation increases in both conditions, but with higher activity during emotion conditions. In contrast, emotion conflict effects were not found in regions associated with affective processing, such as rostral ACC.These activation patterns provide evidence for a domain-general neural system that is active for both emotional and cognitive conflict processing. In line with previous behavioural evidence, greatest activity in these brain regions occurred when both emotional and cognitive influences additively combined to produce increased interference

Extraction and sensitive detection of toxins A and B from the human pathogen Clostridium difficile in 40 seconds using microwave-accelerated metal-enhanced fluorescence.

Clostridium difficile is the primary cause of antibiotic associated diarrhea in humans and is a significant cause of morbidity and mortality. Thus the rapid and accurate identification of this pathogen in clinical samples, such as feces, is a key step in reducing the devastating impact of this disease. The bacterium produces two toxins, A and B, which are thought to be responsible for the majority of the pathology associated with the disease, although the relative contribution of each is currently a subject of debate. For this reason we have developed a rapid detection assay based on microwave-accelerated metal-enhanced fluorescence which is capable of detecting the presence of 10 bacteria in unprocessed human feces within 40 seconds. These promising results suggest that this prototype biosensor has the potential to be developed into a rapid, point of care, real time diagnostic assay for C. difficile

Responding to GPs' information resource needs: implementation and evaluation of a complementary medicines information resource in Queensland general practice

Background: Australian General Practitioners (GPs) are in the forefront of primary health care and in an excellent position to communicate with their patients and educate them about Complementary Medicines (CMs) use. However previous studies have demonstrated that GPs lack the knowledge required about CMs to effectively communicate with patients about their CMs use and they perceive a need for information resources on CMs to use in their clinical practice. This study aimed to develop, implement, and evaluate a CMs information resource in Queensland (Qld) general practice.Methods: The results of the needs assessment survey of Qld general practitioners (GPs) informed the development of a CMs information resource which was then put through an implementation and evaluation cycle in Qld general practice. The CMs information resource was a set of evidence-based herbal medicine fact sheets. This resource was utilised by 100 Qld GPs in their clinical practice for four weeks and was then evaluated. The evaluation assessed GPs' (1) utilisation of the resource (2) perceived quality, usefulness and satisfaction with the resource and (3) perceived impact of the resource on their knowledge, attitudes, and practice of CMs.Results: Ninety two out of the 100 GPs completed the four week evaluation of the fact sheets and returned the post-intervention survey. The herbal medicine fact sheets produced by this study were well accepted and utilised by Qld GPs. The majority of GPs perceived that the fact sheets were a useful resource for their clinical practice. The fact sheets improved GPs' attitudes towards CMs, increased their knowledge of those herbal medicines and improved their communication with their patients about those specific herbs. Eighty-six percent of GPs agreed that if they had adequate resources on CMs, like the herbal medicine fact sheets, then they would communicate more to their patients about their use of CMs.Conclusion: Further educational interventions on CMs need to be provided to GPs to increase their knowledge of CMs and to improve their communication with patients about their CMs use

Characterisation of Clostridium difficile Hospital Ward–Based Transmission Using Extensive Epidemiological Data and Molecular Typing

A population-based study in Oxfordshire (UK) hospitals by Sarah Walker and colleagues finds that in an endemic setting with good infection control, ward-based contact cannot account for most new cases of Clostridium difficile infection