1,994 research outputs found
Insights into the pulmonary vascular complications of heart failure with preserved ejection fraction
Pulmonary hypertension in the setting of heart failure with preserved ejection fraction (PH-HFpEF) is a growing public health problem that is increasing in prevalence. While PH-HFpEF is defined by a high mean pulmonary artery pressure, high left ventricular end-diastolic pressure and a normal ejection fraction, some HFpEF patients develop PH in the presence of pulmonary vascular remodelling with a high transpulmonary pressure gradient or pulmonary vascular resistance. Ageing, increased left atrial pressure and stiffness, mitral regurgitation, as well as features of metabolic syndrome, which include obesity, diabetes and hypertension, are recognized as risk factors for PH-HFpEF. Qualitative studies have documented that patients with PH-HFpEF develop more severe symptoms than those with HFpEF and are associated with more significant exercise intolerance, frequent hospitalizations, right heart failure and reduced survival. Currently, there are no effective therapies for PH-HFpEF, although a number of candidate drugs are being evaluated, including soluble guanylate cyclase stimulators, phosphodiesterase type 5 inhibitors, sodium nitrite and endothelin receptor antagonists. In this review we attempt to provide an updated overview of recent findings pertaining to the pulmonary vascular complications in HFpEF in terms of clinical definitions, epidemiology and pathophysiology. Mechanisms leading to pulmonary vascular remodelling in HFpEF, a summary of pre-clinical models of HFpEF and PH-HFpEF, and new candidate therapeutic strategies for the treatment of PH-HFpEF are summarized
Cadmium burden and the risk and phenotype of prostate cancer
© 2009 Chen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Tunable non-Lifshitz-Kosevich temperature dependence of Shubnikov-de Haas oscillation amplitudes in SmSb
The Lifshitz-Kosevich (LK) theory is the pillar of magnetic quantum
oscillations, which have been extensively applied to characterize a wide range
of metallic states. In this study, we focus on the Shubnikov-de Haas (SdH)
effect observed in SmSb, a rare-earth monopnictide. We observed a significant
departure from the expected LK theory near ~K: both a peak-like
anomaly and an enhancement in the temperature dependence of quantum oscillation
amplitude are seen in SmSb. Moreover, we discovered a remarkable sensitivity of
the SdH amplitudes to sample purity. By adjusting the sample purity, we were
able to tune the temperature dependence of the band's SdH amplitudes
from a peak-like anomalous behavior to an enhancement. Therefore, SdH
oscillations from the band connect the two well-known non-LK
behaviours, controllable through varying the sample purity, paving the way for
developing further understanding of the mechanism leading to the anomalous
quantum oscillations.Comment: 4 figure
Spatial patterns and source attribution of urban methane in the Los Angeles Basin
Urban areas are increasingly recognized as a globally important source of methane to the atmosphere; however, the location of methane sources and relative contributions of source sectors are not well known. Recent atmospheric measurements in Los Angeles, California, USA, show that more than a third of the city's methane emissions are unaccounted for in inventories and suggest that fugitive fossil emissions are the unknown source. We made on-road measurements to quantify fine-scale structure of methane and a suite of complementary trace gases across the Los Angeles Basin in June 2013. Enhanced methane levels were observed across the basin but were unevenly distributed in space. We identified 213 methane hot spots from unknown emission sources. We made direct measurements of ethane to methane (C_2H_6/CH_4) ratios of known methane emission sources in the region, including cattle, geologic seeps, landfills, and compressed natural gas fueling stations, and used these ratios to determine the contribution of biogenic and fossil methane sources to unknown hot spots and to local urban background air. We found that 75% of hot spots were of fossil origin, 20% were biogenic, and 5% of indeterminate source. In regionally integrated air, we observed a wider range of C_2H_6/CH_4 values than observed previously. Fossil fuel sources accounted for 58â65% of methane emissions, with the range depending on the assumed C_2H_6/CH_4 ratio of source end-members and model structure. These surveys demonstrated the prevalence of fugitive methane emissions across the Los Angeles urban landscape and suggested that uninventoried methane sources were widely distributed and primarily of fossil origin
The synthesis of trifluoromethylated N-nitroaryl-2-amino-1,3-dichloropropane derivatives and their evaluation as potential anti-cancer agents
Six N-nitroaryl-2-amino-1,3-dichloropropane derivatives have been prepared and evaluated against 18 cancer cell lines and two non-cancerous cell lines. Analysis of cell viability data and IC50 values indicated that the presence of a trifluoromethyl group in the nitroaryl moiety is an important structural feature associated with the compoundsâ cytotoxicities
Gender Inequality Affecting Womenâs Career Progression in Malaysia
The objective of this research is to assess whether gender inequality affects womenâs career progression in Malaysia. The study examines the relationship between patriarchy, gender stereotypes, organisational cultural factors, family factors, and individual factors with womenâs career progression. The study has adopted the Glass Ceiling Theory and feminist theory. A total of 250 questionnaires were collected from women employees working in Malaysia. The study revealed that patriarchy, organisational cultural factors, and family factors had a significant relationship with womenâs career progression while gender stereotypes and individual factors had no significant relationship with womenâs career progression. The findings of this study contribute to womenâs empowerment in society, and for companies and the Government of Malaysia to have a better understanding of the factors involved in womenâs career progression in Malaysia. This study contributes to the Glass Ceiling Theory and feminist thought by determining the relationship of these theories with regard to womenâs career progression in Malaysia
Lâimpact de la grossesse sur lâamplitude et la diversitĂ© de la reconnaissance antigĂ©nique des lymphocytes T cytotoxiques dirigĂ©s contre le VIH-1
La transmission mĂšre-enfant (TME) du VIH-1 est un des enjeux majeurs de la pandĂ©mie. Une meilleure comprĂ©hension de la rĂ©ponse des lymphocytes T cytotoxiques CD8+ (LTC) VIH-spĂ©cifiques lors de la grossesse facilitera le design de stratĂ©gies optimales pour diminuer la TME. Notre objectif est donc de caractĂ©riser lâamplitude et la diversitĂ© de la reconnaissance antigĂ©nique des LTC VIH-spĂ©cifiques avant, pendant et aprĂšs la grossesse chez des femmes infectĂ©es par le VIH-1. Nos rĂ©sultats montrent pour la premiĂšre fois que lâinitiation et la progression de la grossesse, Ă elles seules, n'ont que peu dâinfluence sur lâamplitude et la diversitĂ© de la reconnaissance antigĂ©nique des rĂ©ponses LTC en termes de production dâIFNâï§. Ces rĂ©sultats indiquent que les femmes infectĂ©es par le VIH conservent une immunocompĂ©tence durant leur grossesse, du moins dans le contexte dâun traitement antirĂ©troviral efficace. Ceci pourrait Ă©ventuellement aider Ă promouvoir lâimmunisation comme stratĂ©gie pour prĂ©venir la TME du VIHâ1.Mother-to-child transmission (MTCT) of HIV-1 is one of the major issues of the pandemic. Characterization of HIV-specific immunity during pregnancy, especially cytotoxic CD8+ T lymphocytes (CTL), will lead to a better understanding of HIV pathogenesis and facilitate design of optimal strategies to prevent MTCT. Our objective is to describe the magnitude and the breadth of antigen recognition of HIV-specific CTL responses before, throughout and after pregnancy in a group of HIV-infected women. Our results revealed for the first time that initiation of pregnancy by itself doesnât change the magnitude of CTL responses in terms of IFN-ï§ production. These findings support the fact that HIV-infected women maintain immunocompetence throughout gestation, at least in the context of effective antiretroviral treatment. These results provide a novel understanding of the dynamics of HIV-specific CTL responses during pregnancy and may help to promote maternal immunization as a strategy to prevent MTCT of HIV-1
Exploring novel correlations in trilepton channels at the LHC for the minimal supersymmetric inverse seesaw model
We investigate signatures of the minimal supersymmetric inverse seesaw model
at the large hadron collider (LHC) with three isolated leptons and large
missing energy (3\ell + \mET or 2\ell + 1\tau + \mET, with \ell=e,\mu) in the
final state. This signal has its origin in the decay of chargino-neutralino
(\chpm1\ntrl2) pair, produced in pp collisions. The two body decays of the
lighter chargino into a charged lepton and a singlet sneutrino has a
characteristic decay pattern which is correlated with the observed large
atmospheric neutrino mixing angle. This correlation is potentially observable
at the LHC by looking at the ratios of cross sections of the trilepton + \mET
channels in certain flavour specific modes. We show that even after considering
possible leading standard model backgrounds these final states can lead to
reasonable discovery significance at the LHC with both 7 TeV and 14 TeV
center-of-mass energy.Comment: 28 pages, 9 .eps figures. 3 new figures and discussions on LHC
observables added, minor modifications in text and in the abstract, 23 new
references added, matches with the published version in JHE
Do 2H and 18O in leaf water reflect environmental drivers differently?
We compiled hydrogen and oxygen stable isotope compositions (ÎŽ H and ÎŽ O) of leaf water from multiple biomes to examine variations with environmental drivers. Leaf water ÎŽ H was more closely correlated with ÎŽ H of xylem water or atmospheric vapour, whereas leaf water ÎŽ O was more closely correlated with air relative humidity. This resulted from the larger proportional range for ÎŽ H of meteoric waters relative to the extent of leaf water evaporative enrichment compared with ÎŽ O. We next expressed leaf water as isotopic enrichment above xylem water (Î H and Î O) to remove the impact of xylem water isotopic variation. For Î H, leaf water still correlated with atmospheric vapour, whereas Î O showed no such correlation. This was explained by covariance between air relative humidity and the Î O of atmospheric vapour. This is consistent with a previously observed diurnal correlation between air relative humidity and the deuterium excess of atmospheric vapour across a range of ecosystems. We conclude that H and O in leaf water do indeed reflect the balance of environmental drivers differently; our results have implications for understanding isotopic effects associated with water cycling in terrestrial ecosystems and for inferring environmental change from isotopic biomarkers that act as proxies for leaf water
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