66 research outputs found
Assessment of different urban traffic control strategy impacts on vehicle emissions
This paper investigates the influence of traffic signal control strategy on vehicle emissions, vehicle journey time and total throughput flow within a single isolated four-armed junction. Two pre-timed signal plans are considered, one with two-stages involving permissive-only opposing turns and the other with four-stages which has no conflicting traffic. Additionally, the increase in efficiency by utilising actuated signal timing where green time is re-optimised as flow values vary is investigated. A microscopic traffic simulation model is used to model flows and AIRE (Analysis of Instantaneous Road Emissions) microscopic emissions model is utilised to out- put emission levels from the flow data. A simple junction model shows that the two-stage signal plan is more efficient in both emis- sions and journey time. However, as the level of opposed turning vehicles and conflicting movement increases, the two-stage model moves to being the inferior signal plan choice and the four-stage plan outputs fewer emissions than the two-stage plan. A real-world example of a four-armed junction has been used in this study and from the traffic survey data and existing junction layout; it is rec- ommended that a two-stage plan is used as it produces lower amounts of emissions and shorter journey times compared to a four-stage plan. The results also show that nitrogen oxides (NOx) are the most sensitive to changes in flow followed by carbon dioxide (CO2), Black Carbon and then particulate matter (PM10)
Environmental impact of combined ITS traffic management strategies
Transport was responsible for 20% of the total greenhouse gas emissions in Europe during 2011 (European Environmental Agency 2013) with road transport being the key contributor. To tackle this, targets have been established in Europe and worldwide to curb transport emissions. This poses a significant challenge on Local Government and transport operators who need to identify a set of effective measures to reduce the environmental impact of road transport and at the same time keep the traffic smooth. Of the road transport pollutants, this paper considers NOx, CO2 and black carbon (BC). A particular focus is put on black carbon, which is formed through incomplete combustion of carboneous materials, as it has a significant impact on the Earthâs climate system. It absorbs solar radiation, influences cloud processes, and alters the melting of snow and ice cover (Bond et al. 2013). BC also causes serious health concerns: black carbon is associated with asthma and other respiratory problems, heart attacks and lung cancer (Sharma 2010; United States Environmental Protection Agency 2012). Since BC emissions are mainly produced during the decelerating and accelerating phases (Zhang et al. 2009), ITS actions able to reduce stop&go phases have the potential to reduce BC emissions. This paper investigates the effectiveness of combined ITS actions in urban context in reducing CO2 and BC emissions and improving traffic conditions
Magneto-optic Kerr effect in a spin-polarized zero-moment ferrimagnet
The magneto-optical Kerr effect (MOKE) is often assumed to be proportional to
the magnetisation of a magnetically ordered metallic sample; in metallic
ferrimagnets with chemically distinct sublattices, such as rare-earth
transition-metal alloys, it depends on the difference between the sublattice
contributions. Here we show that in a highly spin polarized, fully compensated
ferrimagnet, where the sublattices are chemically similar, MOKE is observed
even when the net moment is strictly zero. We analyse the spectral ellipsometry
and MOKE of Mn 2 Ru x Ga, and show that this behaviour is due to a highly
spin-polarized conduction band dominated by one of the two manganese
sublattices which creates helicity-dependent reflectivity determined by a broad
Drude tail. Our findings open new prospects for studying spin dynamics in the
infra-red.Comment: 7 pages, 7 figure
Designing a fully compensated half-metallic ferrimagnet
Recent experimental work on Mn2RuxGa demonstrates its potential as a compensated ferrimagnetic
half-metal (CFHM). Here we present a set of high-throughput ab initio density functional
theory calculations and detailed experimental characterisation, that enable us to correctly describe
the nominal Mn2RuxGa thin films, in particular with regard to site-disorder and defects. We then
construct models that accurately capture all the key features of the Mn-Ru-Ga system, including
magnetic compensation and the spin gap at the Fermi level. We find that electronic doping is neccessary,
which is achieved with a Mn/Ga ratio smaller than two. Our study shows how composition
and substrate-induced biaxial strain can be combined to design a ferrimagnetic half-metal with a
compensation point close to room temperature
Lipodystrophy-Linked LMNA p.R482W Mutation Induces Clinical Early Atherosclerosis and In Vitro Endothelial Dysfunction
ObjectiveâSome mutations in LMNA, encoding A-type lamins, are responsible for Dunnigan-type-familial partial lipodystrophy (FPLD2), with altered fat distribution and metabolism. The high prevalence of early and severe cardiovascular outcomes in these patients suggests that, in addition to metabolic risk factors, FPLD2-associated LMNA mutations could have a direct role on the vascular wall cells.
Approach and ResultsâWe analyzed the cardiovascular phenotype of 19 FPLD2 patients aged >30 years with LMNA p.R482 heterozygous substitutions, and the effects of p.R482W-prelamin-A overexpression in human coronary artery endothelial cells. In 68% of FPLD2 patients, early atherosclerosis was attested by clinical cardiovascular events, occurring before the age of 45 in most cases. In transduced endothelial cells, exogenous wild-type-prelamin-A was correctly processed and localized, whereas p.R482W-prelamin-A accumulated abnormally at the nuclear envelope. Patientsâ fibroblasts also showed a predominant nuclear envelope distribution with a decreased rate of prelamin-A maturation. Only p.R482W-prelamin-A induced endothelial dysfunction, with decreased production of NO, increased endothelial adhesion of peripheral blood mononuclear cells, and cellular senescence. p.R482W-prelamin-A also induced oxidative stress, DNA damages, and inflammation. These alterations were prevented by treatment of endothelial cells with pravastatin, which inhibits prelamin-A farnesylation, or with antioxidants. In addition, pravastatin allowed the correct relocalization of p.R482W-prelamin-A within the endothelial cell nucleus. These data suggest that farnesylated p.R482W-prelamin-A accumulation at the nuclear envelope is a toxic event, leading to cellular oxidative stress and endothelial dysfunction.
ConclusionsâLMNA p.R482 mutations, responsible for FPLD2, exert a direct proatherogenic effect in endothelial cells, which could contribute to patientsâ early atherosclerosis
Complex interaction of obesity, intentional weight loss and heart failure: a systematic review and meta-analysis
OBJECTIVE:The aim of the meta-analysis was to determine the association of obesity and heart failure (HF) and the cardiac impact of intentional weight loss following bariatric surgery on cardiac structure and myocardial function in obese subjects. METHODS:MEDLINE, Embase and Web of Science were searched up to 3 April 2018. Studies reporting association and prognostic impact of obesity in HF and the impact of intentional weight loss following bariatric surgery on cardiac structure and myocardial function in obesity were included in the meta-analysis. RESULTS:4959 citations were reviewed. After exclusions, 29 studies were analysed. A 'J curve' relationship was observed between body mass index (BMI) and risk of HF with maximum risk in the morbidly obese (1.73 (95% CI 1.30 to 2.31), p<0.001, n=11). Although 'obesity paradox' was observed for all-cause mortality, the overweight group was associated with lower cardiovascular (CV) mortality (OR=0.86 (95% CI 0.79 to 0.94), n=11) with no significant differences across other BMI groups. Intentional weight loss induced by bariatric surgery in obese patients (n=9) without established HF, atrial fibrillation or known coronary artery disease, was associated with a reduction in left ventricular mass index (p<0.0001), improvement in left ventricular diastolic function (pâ€0.0001) and a reduction in left atrial size (p=0.02). CONCLUSIONS:Despite the increased risk of HF with obesity, an 'obesity paradox' is observed for all-cause mortality. However, the nadir for CV mortality is observed in the overweight group. Importantly, intentional weight loss was associated with improvement in indices of cardiac structure and myocardial function in obese patients. TRIAL REGISTRATION NUMBER:APP 74412.Rajiv Mahajan, Michael Stokes, Adrian Elliott, Dian A Munawar, Kashif B Khokhar, Anand Thiyagarajah, Jeroen Hendriks, Dominik Linz, Celine Gallagher, David Kaye, Dennis Lau, Prashanthan Sander
Narrow-band tunable terahertz emission from ferrimagnetic Mn3-xGa thin films
Narrow-band terahertz emission from coherently excited spin precession in metallic ferrimagnetic Mn3-xGa Heusler alloy nanofilms has been observed. The efficiency of the emission, per nanometer film thickness, is comparable or higher than that of classical laser-driven terahertz sources based on optical rectification. The center frequency of the emission from the films can be tuned precisely via the film composition in the range of 0.20-0.35 THz, making this type of metallic film a candidate for efficient on-chip terahertz emitters. Terahertz emission spectroscopy is furthermore shown to be a sensitive probe of magnetic properties of ultra-thin films. Published by AIP Publishing
Membrane transport, sensing and signaling in plant adaptation to environmental stress
Plants are generally well adapted to a wide range of environmental conditions. Even though they have notably prospered in our planet, stressful conditions such as salinity, drought and cold or heat, which are increasingly being observed worldwide in the context of the ongoing climate changes, limit their growth and productivity. Behind the remarkable ability of plants to cope with these stresses and still thrive, sophisticated and efficient mechanisms to re-establish and maintain ion and cellular homeostasis are involved. Among the plant arsenal to keep homeostasis are efficient stress sensing and signaling mechanisms, plant cell detoxification systems, compatible solute and osmoprotectant accumulation and a vital rearrangement of solute transport and compartmentation. The key role of solute transport systems and signaling proteins in cellular homeostasis is addressed in the present work. The full understanding of the plant cell complex defense mechanisms under stress may allow for the engineering of more tolerant plants or the optimization of cultivation practices to improve yield and productivity, which is crucial in the present time as food resources are progressively scarce.This work was supported by the Portuguese Foundation for Science and Technology (FCT)
(research project ref. PTDC/AGR-ALI/100636/2008; to A. Conde, grant ref.
SFRH/BD/47699/2008)
Daratumumab plus bortezomib and dexamethasone versus bortezomib and dexamethasone in relapsed or refractory multiple myeloma: updated analysis of CASTOR
Daratumumab, a CD38 human monoclonal antibody, demonstrated significant clinical activity in combination with bortezomib and dexamethasone versus bortezomib and dexamethasone alone in the primary analysis of CASTOR, a phase 3 study in relapsed and/or refractory multiple myeloma. A post hoc analysis based on treatment history and longer follow-up is presented. After 19.4 (range: 0 to 27.7) months of median follow-up, daratumumab plus bortezomib and dexamethasone prolonged progression-free survival (median: 16.7 versus 7.1 months; hazard ratio, 0.31; 95% confidence interval, 0.24-0.39; P 12, 646, or >6 months), or cytogenetic risk. Minimal residual disease-negative rates were >2.5-fold higher with daratumumab across subgroups. The safety profile of daratumumab plus bortezomib and dexamethasone remained consistent with longer follow-up. Daratumumab plus bortezomib and dexamethasone demonstrated significant clinical activity across clinically relevant subgroups and provided the greatest benefit to patients treated at first relapse
The development of leaf succulence in the halophyte Suaeda maritima (L>) Dum
SIGLEAvailable from British Library Document Supply Centre-DSC:DXN007492 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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