288 research outputs found

    Plant Biomarker Pattern, Apples grown with various availability of organic nitrogen and with or witout the use of pesticides

    Get PDF
    In the recent years there has been an increasing focus on the quality and health value of organic plant products compared with conventional products. The use of pesticides and concentrated fertilisers in conventional agriculture implies a risk of effects on plant composition, which may affect health of the consumer (Brandt & Mølgaard, 2001). To determine if organically grown plant food could provide more or less benefits to health than conventional food, a first step is to investigate the differences in the composition and relative concentration of natural compounds in the plant products. In this project apples were grown with two levels of nitrogen availability and with or without the use of pesticides. The apples were screened for changes in the phytochemical composition and concentration. The work is affiliated to the project "Organic food and health" supported by the Danish Research Centre for Organic Farming (DARCOF). Biomarkers and biomarker patterns were presented in plants cultivated with low and high N and with pesticides. One biomarker was related to: • the type of N with and without pesticides • pesticides at high N and type of N without pesticides • pesticides at low and high N One biomarker pattern was related to: • the type of N • the type of N without pesticides • pesticides at low N and type of N without pesticides • pesticides at high N and type of N with pesticide

    Analytical approximation of the stress-energy tensor of a quantized scalar field in static spherically symmetric spacetimes

    Get PDF
    Analytical approximations for {} and {} of a quantized scalar field in static spherically symmetric spacetimes are obtained. The field is assumed to be both massive and massless, with an arbitrary coupling ξ\xi to the scalar curvature, and in a zero temperature vacuum state. The expressions for {} and {} are divided into low- and high-frequency parts. The contributions of the high-frequency modes to these quantities are calculated for an arbitrary quantum state. As an example, the low-frequency contributions to {} and {} are calculated in asymptotically flat spacetimes in a quantum state corresponding to the Minkowski vacuum (Boulware quantum state). The limits of the applicability of these approximations are discussed.Comment: revtex4, 17 pages; v2: three references adde

    Determinants on lens spaces and cyclotomic units

    Full text link
    The Laplacian functional determinants for conformal scalars and coexact one-forms are evaluated in closed form on inhomogeneous lens spaces of certain orders, including all odd primes when the essential part of the expression is given, formally as a cyclotomic unitComment: 18 pages, 1 figur

    Improved overall survival after implementation of targeted therapy for patients with metastatic renal cell carcinoma: Results from the Danish Renal Cancer Group (DARENCA) study-2

    Get PDF
    AbstractAimTo evaluate the implementation of targeted therapy on overall survival (OS) in a complete national cohort of patients with metastatic renal cell carcinoma (mRCC).MethodsAll Danish patients with mRCC referred for first line treatment with immunotherapy, TKIs or mTOR-inhibitors between 2006 and 2010 were included. Baseline and outcome data were collected retrospectively. Prognostics factors were identified using log-rank tests and Cox proportional hazard model. Differences in distributions were tested with the Chi-square test.Results1049 patients were referred; 744 patients received first line treatment. From 2006 to 2010 we observed a significant increase in the number of referred patients; a significant increase in treated patients (64% versus 75%, P=0.0188); a significant increase in first line targeted therapy (22% versus 75%, P<0.0001); a significant increase in second line treatment (20% versus 40%, P=0.0104), a significant increased median OS (11.5 versus 17.2 months, P=0.0435) whereas survival for untreated patients remained unchanged. Multivariate analysis validated known prognostic factors. Moreover, treatment start years 2008 (HR 0.74, 95% CI, 0.55–0.99; P=0.0415), 2009 (HR 0.72, 95% CI, 0.54–0.96; P=0.0277) and 2010 (HR 0.63, 95% CI, 0.47–0.86; P=0.0035) compared to 2006, and more than two treatment lines received for patients with performance status 0–1 (HR 0.76, 95% CI, 0.58–0.99; P=0.0397) and performance status 2–3 (HR 0.19, 95% CI, 0.06–0.60; P=0.0051) were significantly associated with longer OS.ConclusionThis retrospective study documents that the implementation of targeted therapy has resulted in significantly improved treatment rates and overall survival in a complete national cohort of treated mRCC patients

    Surfactant-Free Colloidal Syntheses of Gold-Based Nanomaterials in Alkaline Water and Mono-alcohol Mixtures [Dataset]

    Get PDF
    120 pages. -- SA. Synthesis of Au NPs using ROH. -- SB. Experimental section. -- SC. Effect of mono-alcohol, mono-alcohol content and cation. -- SD. Effect of experimental parameters: HAuCl4 concentration, volume of solution, type of container used, light. -- SE. Effect of the nature of the alcohols. -- SF. Kinetics of the reduction. -- SG. Influence of the temperature. -- SH. Influence of base concentration. -- SI. Influence of gas atmosphere. -- SJ. Influence of the order of addition of the chemicals. -- SK. Discussion of Au NP formation. -- SL. Reproducibility. -- SM. Scalability. -- SN. Mixture of mono-alcohols. -- SO. Cation and surfactant effects . -- SP. Electrochemical characterization of Au NPs. -- SQ. Supported NPs. -- SR. Pd and bimetallic NPs. -- SS. Nanocomposites. -- ST. Electrochemical characterization of AuxPdy NPs and [x Au + y Pd] nanocomposites. -- SU. Outlook into multi-metallic nanomaterials. -- SV. Comparison of different catalysts. -- SW. ReferencesGold nanoparticles (Au NPs) and gold-based nanomaterials combine unique properties relevant for medicine, imaging, optics, sensing, catalysis, and energy conversion. While the Turkevich–Frens and Brust–Schiffrin methods remain the state-of-the-art colloidal syntheses of Au NPs, there is a need for more sustainable and tractable synthetic strategies leading to new model systems. In particular, stabilizers are almost systematically used in colloidal syntheses, but they can be detrimental for fundamental and applied studies. Here, a surfactant-free synthesis of size-controlled colloidal Au NPs stable for months is achieved by the simple reduction of HAuCl4 at room temperature in alkaline solutions of low-viscosity mono-alcohols such as ethanol or methanol and water, without the need for any other additives. Palladium (Pd) and bimetallic AuxPdy NPs, nanocomposites and multimetallic samples, are also obtained and are readily active (electro)­catalysts. The multiple benefits over the state-of-the-art syntheses that this simple synthesis bears for fundamental and applied research are highlighted.Peer reviewe

    BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers

    Get PDF
    Background: The K3326X variant in BRCA2 (BRCA2*c.9976A&gt;T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers. Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided. Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptor–negative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed. Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations

    Stochastic Gravity: Theory and Applications

    Get PDF
    Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel.In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime: we compute the two-point correlation functions for the linearized Einstein tensor and for the metric perturbations. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit

    Stochastic Gravity: Theory and Applications

    Get PDF
    Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel. In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime, compute the two-point correlation functions of these perturbations and prove that Minkowski spacetime is a stable solution of semiclassical gravity. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a black hole and describe the metric fluctuations near the event horizon of an evaporating black holeComment: 100 pages, no figures; an update of the 2003 review in Living Reviews in Relativity gr-qc/0307032 ; it includes new sections on the Validity of Semiclassical Gravity, the Stability of Minkowski Spacetime, and the Metric Fluctuations of an Evaporating Black Hol

    Robust Tests for Additive Gene-Environment Interaction in Case-Control Studies Using Gene-Environment Independence

    Get PDF
    There have been recent proposals advocating the use of additive gene-environment interaction instead of the widely used multiplicative scale, as a more relevant public health measure. Using gene-environment independence enhances statistical power for testing multiplicative interaction in case-control studies. However, under departure from this assumption, substantial bias in the estimates and inflated type I error in the corresponding tests can occur. In this paper, we extend the empirical Bayes (EB) approach previously developed for multiplicative interaction, which trades off between bias and efficiency in a data-adaptive way, to the additive scale. An EB estimator of the relative excess risk due to interaction is derived, and the corresponding Wald test is proposed with a general regression setting under a retrospective likelihood framework. We study the impact of gene-environment association on the resultant test with case-control data. Our simulation studies suggest that the EB approach uses the gene-environment independence assumption in a data-adaptive way and provides a gain in power compared with the standard logistic regression analysis and better control of type I error when compared with the analysis assuming gene-environment independence. We illustrate the methods with data from the Ovarian Cancer Association Consortium.Multiple funders listed on paper

    A Reduction in Ribonucleotide Reductase Activity Slows Down the Chromosome Replication Fork but Does Not Change Its Localization

    Get PDF
    BACKGROUND:It has been proposed that the enzymes of nucleotide biosynthesis may be compartmentalized or concentrated in a structure affecting the organization of newly replicated DNA. Here we have investigated the effect of changes in ribonucleotide reductase (RNR) activity on chromosome replication and organization of replication forks in Escherichia coli. METHODOLOGY/PRINCIPAL FINDINGS:Reduced concentrations of deoxyribonucleotides (dNTPs) obtained by reducing the activity of wild type RNR by treatment with hydroxyurea or by mutation, resulted in a lengthening of the replication period. The replication fork speed was found to be gradually reduced proportionately to moderate reductions in nucleotide availability. Cells with highly extended C periods showed a "delay" in cell division i.e. had a higher cell mass. Visualization of SeqA structures by immunofluorescence indicated no change in organization of the new DNA upon moderate limitation of RNR activity. Severe nucleotide limitation led to replication fork stalling and reversal. Well defined SeqA structures were not found in situations of extensive replication fork repair. In cells with stalled forks obtained by UV irradiation, considerable DNA compaction was observed, possibly indicating a reorganization of the DNA into a "repair structure" during the initial phase of the SOS response. CONCLUSION/SIGNIFICANCE:The results indicate that the replication fork is slowed down in a controlled manner during moderate nucleotide depletion and that a change in the activity of RNR does not lead to a change in the organization of newly replicated DNA. Control of cell division but not control of initiation was affected by the changes in replication elongation
    corecore