119 research outputs found
Measuring persistent and transient energy efficiency in the US
The promotion of US energy efficiency policy is seen as a very important activity. Generally, the level of energy efficiency of a country or state is approximated by energy intensity, commonly calculated as the ratio of energy use to GDP. However, energy intensity is not an accurate proxy for energy efficiency given that changes in energy intensity are a function of changes in several factors including the structure of the economy, climate, efficiency in the use of resources, behaviour and technical change. The aim of this paper is to measure persistent and transient energy efficiency for the whole economy of 49 states in the US using a stochastic frontier energy demand approach. A total US energy demand frontier function is estimated using panel data for 49 states over the period 1995 to 2009 using two panel data models: the Mundlak version of the random effects model (which estimates the persistent part of the energy efficiency) and the true random effects model (which estimates the transient part of the energy efficiency). The analysis confirms that energy intensity is not a good indicator of energy efficiency, whereas, by controlling for a range of economic and other factors, the measures of energy efficiency obtained via the approach adopted here are. Moreover, the estimates show that although for some states energy intensity might give a reasonable indication of a state’s relative energy efficiency, this is not the case for all states.ISSN:1570-646XISSN:1570-647
Polyamine metabolism is involved in adipogenesis of 3T3-L1 cells
Polyamines spermidine and spermine are known to be required for mammalian cell proliferation and for embryonic development. Alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (ODC) a limiting enzyme of polyamine biosynthesis, depleted the cellular polyamines and prevented triglyceride accumulation and differentiation in 3T3-L1 cells. In this study, to explore the function of polyamines in adipogenesis, we examined the effect of polyamine biosynthesis inhibitors on adipocyte differentiation and lipid accumulation of 3T3-L1 cells. The spermidine synthase inhibitor trans-4-methylcyclohexylamine (MCHA) increased spermine/spermidine ratios, whereas the spermine synthase inhibitor N-(3-aminopropyl)-cyclohexylamine (APCHA) decreased the ratios in the cells. MCHA was found to decrease lipid accumulation and GPDH activity during differentiation, while APCHA increased lipid accumulation and GPDH activity indicating the enhancement of differentiation. The polyamine-acetylating enzyme, spermidine/spermine N1-acetyltransferase (SSAT) activity was increased within a few hours after stimulus for differentiation, and was found to be elevated by APCHA. In mature adipocytes APCHA decreased lipid accumulation while MCHA had the opposite effect. An acetylpolyamine oxidase and spermine oxidase inhibitor MDL72527 or an antioxidant N-acetylcysteine prevented the promoting effect of APCHA on adipogenesis. These results suggest that not only spermine/spermidine ratios but also polyamine catabolic enzyme activity may contribute to adipogenesis
Visualizing variation within Global Pneumococcal Sequence Clusters (GPSCs) and country population snapshots to contextualize pneumococcal isolates
Knowledge of pneumococcal lineages, their geographic distribution and antibiotic resistance patterns, can give insights into
global pneumococcal disease. We provide interactive bioinformatic outputs to explore such topics, aiming to increase dissemination of genomic insights to the wider community, without the need for specialist training. We prepared 12 country-specific
phylogenetic snapshots, and international phylogenetic snapshots of 73 common Global Pneumococcal Sequence Clusters
(GPSCs) previously defined using PopPUNK, and present them in Microreact. Gene presence and absence defined using Roary,
and recombination profiles derived from Gubbins are presented in Phandango for each GPSC. Temporal phylogenetic signal
was assessed for each GPSC using BactDating. We provide examples of how such resources can be used. In our example use of
a country-specific phylogenetic snapshot we determined that serotype 14 was observed in nine unrelated genetic backgrounds
in South Africa. The international phylogenetic snapshot of GPSC9, in which most serotype 14 isolates from South Africa
were observed, highlights that there were three independent sub-clusters represented by South African serotype 14 isolates.
We estimated from the GPSC9-dated tree that the sub-clusters were each established in South Africa during the 1980s. We
show how recombination plots allowed the identification of a 20kb recombination spanning the capsular polysaccharide locus
within GPSC97. This was consistent with a switch from serotype 6A to 19A estimated to have occured in the 1990s from the
GPSC97-dated tree. Plots of gene presence/absence of resistance genes (tet, erm, cat) across the GPSC23 phylogeny were
consistent with acquisition of a composite transposon. We estimated from the GPSC23-dated tree that the acquisition occurred
between 1953 and 1975. Finally, we demonstrate the assignment of GPSC31 to 17 externally generated pneumococcal serotype
1 assemblies from Utah via Pathogenwatch. Most of the Utah isolates clustered within GPSC31 in a USA-specific clade with the
most recent common ancestor estimated between 1958 and 1981. The resources we have provided can be used to explore to
data, test hypothesis and generate new hypotheses. The accessible assignment of GPSCs allows others to contextualize their
own collections beyond the data presented here
Cigarette smoke worsens lung inflammation and impairs resolution of influenza infection in mice
<p>Abstract</p> <p>Background</p> <p>Cigarette smoke has both pro-inflammatory and immunosuppressive effects. Both active and passive cigarette smoke exposure are linked to an increased incidence and severity of respiratory virus infections, but underlying mechanisms are not well defined. We hypothesized, based on prior gene expression profiling studies, that upregulation of pro-inflammatory mediators by short term smoke exposure would be protective against a subsequent influenza infection.</p> <p>Methods</p> <p>BALB/c mice were subjected to whole body smoke exposure with 9 cigarettes/day for 4 days. Mice were then infected with influenza A (H3N1, Mem71 strain), and analyzed 3 and 10 days later (d3, d10). These time points are the peak and resolution (respectively) of influenza infection.</p> <p>Results</p> <p>Inflammatory cell influx into the bronchoalveolar lavage (BALF), inflammatory mediators, proteases, histopathology, viral titres and T lymphocyte profiles were analyzed. Compared to smoke or influenza alone, mice exposed to smoke and then influenza had more macrophages, neutrophils and total lymphocytes in BALF at d3, more macrophages in BALF at d10, lower net gelatinase activity and increased activity of tissue inhibitor of metalloprotease-1 in BALF at d3, altered profiles of key cytokines and CD4+ and CD8+ T lymphocytes, worse lung pathology and more virus-specific, activated CD8+ T lymphocytes in BALF. Mice smoke exposed before influenza infection had close to 10-fold higher lung virus titres at d3 than influenza alone mice, although all mice had cleared virus by d10, regardless of smoke exposure. Smoke exposure caused temporary weight loss and when smoking ceased after viral infection, smoke and influenza mice regained significantly less weight than smoke alone mice.</p> <p>Conclusion</p> <p>Smoke induced inflammation does not protect against influenza infection.</p> <p>In most respects, smoke exposure worsened the host response to influenza. This animal model may be useful in studying how smoke worsens respiratory viral infections.</p
Vibrio cholerae vexH Encodes a Multiple Drug Efflux Pump That Contributes to the Production of Cholera Toxin and the Toxin Co-Regulated Pilus
The resistance-nodulation-division (RND) efflux systems are ubiquitous transporters that function in antimicrobial resistance. Recent studies showed that RND systems were required for virulence factor production in Vibrio cholerae. The V. cholerae genome encodes six RND efflux systems. Three of the RND systems (VexB, VexD, and VexK) were previously shown to be redundant for in vitro resistance to bile acids and detergents. A mutant lacking the VexB, VexD, and VexK RND pumps produced wild-type levels of cholera toxin (CT) and the toxin co-regulated pilus (TCP) and was moderately attenuated for intestinal colonization. In contrast, a RND negative mutant produced significantly reduced amounts of CT and TCP and displayed a severe colonization defect. This suggested that one or more of the three uncharacterized RND efflux systems (i.e. VexF, VexH, and VexM) were required for pathogenesis. In this study, a genetic approach was used to generate a panel of V. cholerae RND efflux pump mutants in order to determine the function of VexH in antimicrobial resistance, virulence factor production, and intestinal colonization. VexH contributed to in vitro antimicrobial resistance and exhibited a broad substrate specificity that was redundant with the VexB, VexD, and VexK RND efflux pumps. These four efflux pumps were responsible for in vitro antimicrobial resistance and were required for virulence factor production and intestinal colonization. Mutation of the VexF and/or VexM efflux pumps did not affect in vitro antimicrobial resistance, but did negatively affect CT and TCP production. Collectively, our results demonstrate that the V. cholerae RND efflux pumps have redundant functions in antimicrobial resistance and virulence factor production. This suggests that the RND efflux systems contribute to V. cholerae pathogenesis by providing the bacterium with protection against antimicrobial compounds that are present in the host and by contributing to the regulated expression of virulence factors
Exploiting solar visible-range observations by inversion techniques: from flows in the solar subsurface to a flaring atmosphere
Observations of the Sun in the visible spectral range belong to standard
measurements obtained by instruments both on the ground and in the space.
Nowadays, both nearly continuous full-disc observations with medium resolution
and dedicated campaigns of high spatial, spectral and/or temporal resolution
constitute a holy grail for studies that can capture (both) the long- and
short-term changes in the dynamics and energetics of the solar atmosphere.
Observations of photospheric spectral lines allow us to estimate not only the
intensity at small regions, but also various derived data products, such as the
Doppler velocity and/or the components of the magnetic field vector. We show
that these measurements contain not only direct information about the dynamics
of solar plasmas at the surface of the Sun but also imprints of regions below
and above it. Here, we discuss two examples: First, the local time-distance
helioseismology as a tool for plasma dynamic diagnostics in the near subsurface
and second, the determination of the solar atmosphere structure during flares.
The methodology in both cases involves the technique of inverse modelling.Comment: 29 pages, 15 figures. Accepted for publication in the book "Reviews
in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds
Kabath, Jones and Skarka; publisher Springer Nature) funded by the European
Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul"
2017-1-CZ01-KA203-03556
International links between Streptococcus pneumoniae vaccine serotype 4 sequence type (ST) 801 in Northern European shipyard outbreaks of invasive pneumococcal disease
Background: Pneumococcal disease outbreaks of vaccine preventable serotype 4 sequence type (ST)801 in shipyards have been reported in several countries. We aimed to use genomics to establish any international links between them. Methods: Sequence data from ST801-related outbreak isolates from Norway (n = 17), Finland (n = 11) and Northern Ireland (n = 2) were combined with invasive pneumococcal disease surveillance from the respective countries, and ST801-related genomes from an international collection (n = 41 of > 40,000), totalling 106 genomes. Raw data were mapped and recombination excluded before phylogenetic dating. Results: Outbreak isolates were relatively diverse, with up to 100 SNPs (single nucleotide polymorphisms) and a common ancestor estimated around the year 2000. However, 19 Norwegian and Finnish isolates were nearly indistinguishable (0–2 SNPs) with the common ancestor dated around 2017. Conclusion: The total diversity of ST801 within the outbreaks could not be explained by recent transmission alone, suggesting that harsh environmental and associated living conditions reported in the shipyards may facilitate invasion of colonising pneumococci. However, near identical strains in the Norwegian and Finnish outbreaks does suggest that transmission between international shipyards also contributed to those outbreaks. This indicates the need for improved preventative measures in this working population including pneumococcal vaccination
Contributing to food security in urban areas: differences between urban agriculture and peri-urban agriculture in the Global North
Surfing the spectrum - what is on the horizon?
Diagnostic imaging techniques have evolved with technological advancements - but how far? The objective of this article was to explore the electromagnetic spectrum to find imaging techniques which may deliver diagnostic information of equal, or improved, standing to conventional radiographs and to explore any developments within radiography which may yield improved diagnostic data. A comprehensive literature search was performed using Medline, Web of Knowledge, Science Direct and PubMed Databases. Boolean Operators were used and key-terms included (not exclusively): terahertz, X-ray, ultraviolet, visible, infra-red, magnetic resonance, dental, diagnostic, caries and periodontal. Radiographic techniques are primarily used for diagnostic imaging in dentistry, and continued developments in X-ray imaging include: phase contrast, darkfield and spectral imaging. Other modalities have potential application, for example, terahertz, laser doppler and optical techniques, but require further development. In particular, infra-red imaging has regenerated interest with caries detection in vitro, due to improved quality and accessibility of cameras. Non-ionising imaging techniques, for example, infra-red, are becoming more commensurate with traditional radiographic techniques for caries detection. Nevertheless, X-rays continue to be the leading diagnostic image for dentists, with improved diagnostic potential for lower radiation dose becoming a reality
LPS-induced modules of co-expressed genes in equine peripheral blood mononuclear cells
- …