Stacking a 4D geometry into an Einstein-Gauss-Bonnet bulk

In Einstein gravity there is a simple procedure to build D-dimensional spacetimes starting from (D-1)-dimensional ones, by stacking any (D-1)-dimensional Ricci-flat metric into the extra-dimension. We analyze this procedure in the context of Einstein-Gauss-Bonnet gravity, and find that it can only be applied to metrics with a constant Krestschmann scalar. For instance, we show that solutions of the black-string type are not allowed in this framework.Comment: 8 pages, no figures; some references added and other minor modifications to match the PRD accepted versio

Massless Metric Preheating

Can super-Hubble metric perturbations be amplified exponentially during preheating ? Yes. An analytical existence proof is provided by exploiting the conformal properties of massless inflationary models. The traditional conserved quantity \zeta is non-conserved in many regions of parameter space. We include backreaction through the homogeneous parts of the inflaton and preheating fields and discuss the role of initial conditions on the post-preheating power-spectrum. Maximum field variances are strongly underestimated if metric perturbations are ignored. We illustrate this in the case of strong self-interaction of the decay products. Without metric perturbations, preheating in this case is very inefficient. However, metric perturbations increase the maximum field variances and give alternative channels for the resonance to proceed. This implies that metric perturbations can have a large impact on calculations of relic abundances of particles produced during preheating.Comment: 8 pages, 4 colour figures. Version to appear in Phys. Rev. D. Contains substantial new analysis of the ranges of parameter space for which large changes to the inflation-produced power spectrum are expecte

Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor

Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH4)2SO4. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g1 (dry basis) was obtained after 7 days of fermentation.Felisbela Oliveira acknowledges the financial support from Fundação para a Ciência e Tecnologia (FCT) of Portugal through grant SFRH/BD/87953/2012. José Manuel Salgado was supported by grant CEB/N2020–INV/01/2016 from Project ‘‘BIOTECNORTE-Underpinning Biotechnology to foster the north of Portugal bioeconomy’’ (NORTE-01-0145-FEDER-000004). Luı ´s Abrunhosa was supported by grant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte. Noelia Pérez-Rodríguez acknowledges the financial support of FPU fellowship from the Spanish Ministry of Education, Culture and Sports. The authors thank the Spanish Ministry of Economy and Competitiveness for the financial support of this work (Project CTQ2015-71436-C2-1-R), which has partial financial support from the FEDER funds of the European Union.info:eu-repo/semantics/publishedVersio

Impact of cancer and chemotherapy on autonomic nervous system function and cardiovascular reactivity in young adults with cancer: a case-controlled feasibility study

Background Preliminary evidence suggests cancer- and chemotherapy-related autonomic nervous system (ANS) dysfunction may contribute to the increased cardiovascular (CV) morbidity- and mortality-risks in cancer survivors. However, the reliability of these findings may have been jeopardized by inconsistent participant screening and assessment methods. Therefore, good laboratory practices must be established before the presence and nature of cancer-related autonomic dysfunction can be characterized. The purpose of this study was to assess the feasibility of conducting concurrent ANS and cardiovascular evaluations in young adult cancer patients, according to the following criteria: i) identifying methodological pitfalls and proposing good laboratory practice criteria for ANS testing in cancer, and ii) providing initial physiologic evidence of autonomic perturbations in cancer patients using the composite autonomic scoring scale (CASS). Methods Thirteen patients (mixed diagnoses) were assessed immediately before and after 4 cycles of chemotherapy. Their results were compared to 12 sex- and age-matched controls. ANS function was assessed using standardized tests of resting CV (tilt-table, respiratory sinus arrhythmia and Valsalva maneuver) and sudomotor (quantitative sudomotor axon reflex test) reactivity. Cardiovascular reactivity during exercise was assessed using a modified Astrand-Ryhming cycle ergometer protocol. Our feasibility criteria addressed: i) recruitment potential, ii) retention rates, iii) pre-chemotherapy assessment potential, iv) test performance/tolerability, and v) identification and minimizing the influence of potentially confounding medication. T-tests and repeated measures ANOVAs were used to assess between- and within-group differences at baseline and follow-up. Results The overall success rate in achieving our feasibility criteria was 98.4 %. According to the CASS, there was evidence of ANS impairment at baseline in 30.8 % of patients, which persisted in 18.2 % of patients at follow-up, compared to 0 % of controls at baseline or follow-up. Conclusions Results from our feasibility assessment suggest that the investigation of ANS function in young adult cancer patients undergoing chemotherapy is possible. To the best of our knowledge, this is the first study to report CASS-based evidence of ANS impairment and sudomotor dysfunction in any cancer population. Moreover, we provide evidence of cancer- and chemotherapy-related parasympathetic dysfunction – as a possible contributor to the pathogenesis of CV disease in cancer survivors

Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p lt 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p lt 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum