2,535 research outputs found
Towards a universal âbaselineâ characterisation of air masses for high- and low-altitude observing stations using Radon-222
We demonstrate the ability of atmospheric radon concentrations to reliably and unambiguously identify local and
remote terrestrial influences on an air mass, and thereby the potential for alteration of trace gas composition by
anthropogenic and biogenic processes. Based on high accuracy (lower limit of detection 10â40 mBq mâ3), high temporal
resolution (hourly) measurements of atmospheric radon concentration we describe, apply and evaluate a simple two-step
method for identifying and characterising constituent mole fractions in baseline air. The technique involves selecting a
radon-based threshold concentration to identify the âcleanestâ (least terrestrially influenced) air masses, and then
performing an outlier removal step based on the distribution of constituent mole fractions in the identified clean air
masses. The efficacy of this baseline selection technique is tested at three contrasting WMO GAW stations: Cape Grim (a
coastal low-altitude site), Mauna Loa (a remote high-altitude island site), and Jungfraujoch (a continental high-altitude
site). At Cape Grim and Mauna Loa the two-step method is at least as effective as more complicated methods employed to
characterise baseline conditions, some involving up to nine steps. While it is demonstrated that Jungfraujoch air masses
rarely meet the baseline criteria of the more remote sites, a selection method based on a variable monthly radon threshold
is shown to produce credible ânear baselineâ characteristics. The seasonal peak-to-peak amplitude of recent monthly
baseline CO2 mole fraction deviations from the long-term trend at Cape Grim, Mauna Loa and Jungfraujoch are estimated
to be 1.1, 6.0 and 8.1 ppm, respectively
Immune Phenotype and Function of Natural Killer and T Cells in Chronic Hepatitis C Patients Who Received a Single Dose of Anti-MicroRNA-122, RG-101
MicroRNAâ122 is an important host factor for the hepatitis C virus (HCV). Treatment with RGâ101, an Nâacetylgalactosamineâconjugated antiâmicroRNAâ122 oligonucleotide, resulted in a significant viral load reduction in patients with chronic HCV infection. Here, we analyzed the effects of RGâ101 therapy on antiviral immunity. Thirtyâtwo chronic HCV patients infected with HCV genotypes 1, 3, and 4 received a single subcutaneous administration of RGâ101 at 2 mg/kg (n = 14) or 4 mg/kg (n = 14) or received a placebo (n = 2/dosing group). Plasma and peripheral blood mononuclear cells were collected at multiple time points, and comprehensive immunological analyses were performed. Following RGâ101 administration, HCV RNA declined in all patients (mean decline at week 2, 3.27 log10 IU/mL). At week 8 HCV RNA was undetectable in 15/28 patients. Plasma interferonâÎłâinduced protein 10 (IPâ10) levels declined significantly upon dosing with RGâ101. Furthermore, the frequency of natural killer (NK) cells increased, the proportion of NK cells expressing activating receptors normalized, and NK cell interferonâÎł production decreased after RGâ101 dosing. Functional HCVâspecific interferonâÎł Tâcell responses did not significantly change in patients who had undetectable HCV RNA levels by week 8 postâRGâ101 injection. No increase in the magnitude of HCVâspecific Tâcell responses was observed at later time points, including 3 patients who were HCV RNAânegative 76 weeks postdosing. Conclusion: Dosing with RGâ101 is associated with a restoration of NKâcell proportions and a decrease of NK cells expressing activation receptors; however, the magnitude and functionality of ex vivo HCVâspecific Tâcell responses did not increase following RGâ101 injection, suggesting that NK cells, but not HCV adaptive immunity, may contribute to HCV viral control following RGâ101 therapy
Comparative Field Evaluation of Combinations of Long-Lasting Insecticide Treated Nets and Indoor Residual Spraying, Relative to Either Method Alone, for Malaria Prevention in an Area where the main Vector is Anopheles Arabiensis.
Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used together in the same households to improve malaria control despite inconsistent evidence on whether such combinations actually offer better protection than nets alone or IRS alone. Comparative tests were conducted using experimental huts fitted with LLINs, untreated nets, IRS plus untreated nets, or combinations of LLINs and IRS, in an area where Anopheles arabiensis is the predominant malaria vector species. Three LLIN types, OlysetÂź, PermaNet 2.0Âź and Icon LifeÂź nets and three IRS treatments, pirimiphos-methyl, DDT, and lambda cyhalothrin, were used singly or in combinations. We compared, number of mosquitoes entering huts, proportion and number killed, proportions prevented from blood-feeding, time when mosquitoes exited the huts, and proportions caught exiting. The tests were done for four months in dry season and another six months in wet season, each time using new intact nets. All the net types, used with or without IRS, prevented >99% of indoor mosquito bites. Adding PermaNet 2.0Âź and Icon LifeÂź, but not OlysetÂź nets into huts with any IRS increased mortality of malaria vectors relative to IRS alone. However, of all IRS treatments, only pirimiphos-methyl significantly increased vector mortality relative to LLINs alone, though this increase was modest. Overall, median mortality of An. arabiensis caught in huts with any of the treatments did not exceed 29%. No treatment reduced entry of the vectors into huts, except for marginal reductions due to PermaNet 2.0Âź nets and DDT. More than 95% of all mosquitoes were caught in exit traps rather than inside huts. Where the main malaria vector is An. arabiensis, adding IRS into houses with intact pyrethroid LLINs does not enhance house-hold level protection except where the IRS employs non-pyrethroid insecticides such as pirimiphos-methyl, which can confer modest enhancements. In contrast, adding intact bednets onto IRS enhances protection by preventing mosquito blood-feeding (even if the nets are non-insecticidal) and by slightly increasing mosquito mortality (in case of LLINs). The primary mode of action of intact LLINs against An. arabiensis is clearly bite prevention rather than insecticidal activity. Therefore, where resources are limited, priority should be to ensure that everyone at risk consistently uses LLINs and that the nets are regularly replaced before being excessively torn. Measures that maximize bite prevention (e.g. proper net sizes to effectively cover sleeping spaces, stronger net fibres that resist tears and burns and net use practices that preserve net longevity), should be emphasized
On renormalization group flows and the a-theorem in 6d
We study the extension of the approach to the a-theorem of Komargodski and
Schwimmer to quantum field theories in d=6 spacetime dimensions. The dilaton
effective action is obtained up to 6th order in derivatives. The anomaly flow
a_UV - a_IR is the coefficient of the 6-derivative Euler anomaly term in this
action. It then appears at order p^6 in the low energy limit of n-point
scattering amplitudes of the dilaton for n > 3. The detailed structure with the
correct anomaly coefficient is confirmed by direct calculation in two examples:
(i) the case of explicitly broken conformal symmetry is illustrated by the free
massive scalar field, and (ii) the case of spontaneously broken conformal
symmetry is demonstrated by the (2,0) theory on the Coulomb branch. In the
latter example, the dilaton is a dynamical field so 4-derivative terms in the
action also affect n-point amplitudes at order p^6. The calculation in the
(2,0) theory is done by analyzing an M5-brane probe in AdS_7 x S^4.
Given the confirmation in two distinct models, we attempt to use dispersion
relations to prove that the anomaly flow is positive in general. Unfortunately
the 4-point matrix element of the Euler anomaly is proportional to stu and
vanishes for forward scattering. Thus the optical theorem cannot be applied to
show positivity. Instead the anomaly flow is given by a dispersion sum rule in
which the integrand does not have definite sign. It may be possible to base a
proof of the a-theorem on the analyticity and unitarity properties of the
6-point function, but our preliminary study reveals some difficulties.Comment: 41 pages, 5 figure
The effect of graphite and carbon black ratios on conductive ink performance
Conductive inks based on graphite and carbon black are used in a host of applications including energy storage, energy harvesting, electrochemical sensors and printed heaters. This requires accurate control of electrical properties tailored to the application; ink formulation is a fundamental element of this. Data on how formulation relates to properties have tended to apply to only single types of conductor at any time, with data on mixed types of carbon only empirical thus far. Therefore, screen printable carbon inks with differing graphite, carbon black and vinyl polymer content were formulated and printed to establish the effect on rheology, deposition and conductivity. The study found that at a higher total carbon loading ink of 29.4% by mass, optimal conductivity (0.029 Ω cm) was achieved at a graphite to carbon black ratio of 2.6 to 1. For a lower total carbon loading (21.7 mass %), this ratio was reduced to 1.8 to 1. Formulation affected viscosity and hence ink transfer and also surface roughness due to retention of features from the screen printing mesh and the inherent roughness of the carbon components, as well as the ability of features to be reproduced consistently
Expression of Mcm2, geminin and Ki67 in normal oral mucosa, oral epithelial dysplasias and their corresponding squamous-cell carcinomas
Proteins necessary for the normal regulation of the cell cycle include minichromosome maintenance protein 2 (Mcm2) and geminin.
These are overexpressed in several premalignant and malignant tumours. The Mcm2/Ki67 ratio can be used to estimate the
population of cells that are in early G1 (licensed to proliferate), and the geminin/Ki67 ratio can determine the relative length of G1.
A high ratio indicates a short G1 and a high rate of cell proliferation. Mcm2 and geminin have been scarcely explored in oral epithelial
dysplasia (OED) and oral squamous-cell carcinoma (OSCC). The purpose of this study was to identify the expression pattern of
Mcm2, Ki67 and geminin in normal oral mucosa (NOM), OED and their subsequent OSCC, to determine if expression could help
predict the prognosis of OED. Paraffin sections of 41 OED cases that progressed to carcinoma, 40 OED without malignant
progression, 38 OSCC and 15 NOM were immunostained with antibodies against Mcm2, geminin and Ki67. Labelling indices (LIs)
increased progressively from NOM, OED and OSCC (Mcm2, Po0.001; geminin, Po0.001 and Ki67, Po0.001). In all the OED cases
(n Œ 81) the levels of expression of Mcm2 (LI, 73.6), geminin (LI, 24.4) and Ki67 (LI, 44.5) were elevated indicating a constant cellcycle
re-entry. When the OED groups were compared, Mcm2 protein expression was higher in the OED with malignant progression
(P Œ 0.04), likewise there was a significant increase in the Mcm2/Ki67 and geminin/Ki67 ratios (P Œ 0.04 and 0.02 respectively). Mcm2
and geminin proteins seem to be novel biomarkers of growth and may be useful prognostic tools for OED
Common ADRB2 Haplotypes Derived from 26 Polymorphic Sites Direct ÎČ2-Adrenergic Receptor Expression and Regulation Phenotypes
The beta2-adrenergic receptor (beta2AR) is expressed on numerous cell-types including airway smooth muscle cells and cardiomyocytes. Drugs (agonists or antagonists) acting at these receptors for treatment of asthma, chronic obstructive pulmonary disease, and heart failure show substantial interindividual variability in response. The ADRB2 gene is polymorphic in noncoding and coding regions, but virtually all ADRB2 association studies have utilized the two common nonsynonymous coding SNPs, often reaching discrepant conclusions.We constructed the 8 common ADRB2 haplotypes derived from 26 polymorphisms in the promoter, 5'UTR, coding, and 3'UTR of the intronless ADRB2 gene. These were cloned into an expression construct lacking a vector-based promoter, so that beta2AR expression was driven by its promoter, and steady state expression could be modified by polymorphisms throughout ADRB2 within a haplotype. "Whole-gene" transfections were performed with COS-7 cells and revealed 4 haplotypes with increased cell surface beta2AR protein expression compared to the others. Agonist-promoted downregulation of beta2AR protein expression was also haplotype-dependent, and was found to be increased for 2 haplotypes. A phylogenetic tree of the haplotypes was derived and annotated by cellular phenotypes, revealing a pattern potentially driven by expression.Thus for obstructive lung disease, the initial bronchodilator response from intermittent administration of beta-agonist may be influenced by certain beta2AR haplotypes (expression phenotypes), while other haplotypes may influence tachyphylaxis during the response to chronic therapy (downregulation phenotypes). An ideal clinical outcome of high expression and less downregulation was found for two haplotypes. Haplotypes may also affect heart failure antagonist therapy, where beta2AR increase inotropy and are anti-apoptotic. The haplotype-specific expression and regulation phenotypes found in this transfection-based system suggest that the density of genetic information in the form of these haplotypes, or haplotype-clusters with similar phenotypes can potentially provide greater discrimination of phenotype in human disease and pharmacogenomic association studies
Sociological and Communication-Theoretical Perspectives on the Commercialization of the Sciences
Both self-organization and organization are important for the further
development of the sciences: the two dynamics condition and enable each other.
Commercial and public considerations can interact and "interpenetrate" in
historical organization; different codes of communication are then
"recombined." However, self-organization in the symbolically generalized codes
of communication can be expected to operate at the global level. The Triple
Helix model allows for both a neo-institutional appreciation in terms of
historical networks of university-industry-government relations and a
neo-evolutionary interpretation in terms of three functions: (i) novelty
production, (i) wealth generation, and (iii) political control. Using this
model, one can appreciate both subdynamics. The mutual information in three
dimensions enables us to measure the trade-off between organization and
self-organization as a possible synergy. The question of optimization between
commercial and public interests in the different sciences can thus be made
empirical.Comment: Science & Education (forthcoming
Study of ZÎł events and limits on anomalous ZZÎł and Zγγ couplings in ppÌ collisions at s=1.96TeV
We present a measurement of the ZÎł production cross section and limits on anomalous ZZÎł and Zγγ couplings for form-factor scales of Î=750 and 1000 GeV. The measurement is based on 138 (152) candidates in the eeÎł (ÎŒÎŒÎł) final state using 320(290)pb-1 of ppÌ collisions at s=1.96TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h10,30Z|<0.23, |h20,40Z|<0.020, |h10,30Îł|<0.23, and |h20,40Îł|<0.019 for Î=1000GeV. © 2005 The American Physical Society
Prolonged dopamine signalling in striatum signals proximity and value of distant rewards
Predictions about future rewarding events have a powerful influence on behaviour. The phasic spike activity of dopamine-containing neurons, and corresponding dopamine transients in the striatum, are thought to underlie these predictions, encoding positive and negative reward prediction errors. However, many behaviours are directed towards distant goals, for which transient signals may fail to provide sustained drive. Here we report an extended mode of reward-predictive dopamine signalling in the striatum that emerged as rats moved towards distant goals. These dopamine signals, which were detected with fast-scan cyclic voltammetry (FSCV), gradually increased orâin rare instancesâdecreased as the animals navigated mazes to reach remote rewards, rather than having phasic or steady tonic profiles. These dopamine increases (ramps) scaled flexibly with both the distance and size of the rewards. During learning, these dopamine signals showed spatial preferences for goals in different locations and readily changed in magnitude to reflect changing values of the distant rewards. Such prolonged dopamine signalling could provide sustained motivational drive, a control mechanism that may be important for normal behaviour and that can be impaired in a range of neurologic and neuropsychiatric disorders.National Institutes of Health (U.S.) (Grant R01 MH060379)National Parkinson Foundation (U.S.)Cure Huntingtonâs Disease Initiative, Inc. (Grant A-5552)Stanley H. and Sheila G. Sydney Fun
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