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Organic-inorganic perovskites have shown promise as high-performance absorbers in solar cells, first as a coating on a mesoporous metal oxide scaffold and more recently as a solid layer in planar heterojunction architectures. Here, we report transient absorption and photoluminescence-quenching measurements to determine the electron-hole diffusion lengths, diffusion constants, and lifetimes in mixed halide (CH3NH3PbI(3-x)Cl(x)) and triiodide (CH3NH3PbI3) perovskite absorbers. We found that the diffusion lengths are greater than 1 micrometer in the mixed halide perovskite, which is an order of magnitude greater than the absorption depth. In contrast, the triiodide absorber has electron-hole diffusion lengths of ~100 nanometers. These results justify the high efficiency of planar heterojunction perovskite solar cells and identify a critical parameter to optimize for future perovskite absorber development.

The idea that excitonic (electronic) coherences are of fundamental importance to natural photosynthesis gained popularity when slowly dephasing quantum beats (QBs) were observed in the two-dimensional electronic spectra of the Fenna–Matthews–Olson (FMO) complex at 77 K. These were assigned to superpositions of excitonic states, a controversial interpretation, as the strong chromophore–environment interactions in the complex suggest fast dephasing. Although it has been pointed out that vibrational motion produces similar spectral signatures, a concrete assignment of these oscillatory signals to distinct physical processes is still lacking. Here we revisit the coherence dynamics of the FMO complex using polarization-controlled two-dimensional electronic spectroscopy, supported by theoretical modelling. We show that the long-lived QBs are exclusively vibrational in origin, whereas the dephasing of the electronic coherences is completed within 240 fs even at 77 K. We further find that specific vibrational coherences are produced via vibronically coupled excited states. The presence of such states suggests that vibronic coupling is relevant for photosynthetic energy transfer.

In oxygenic photosynthetic eukaryotes, the hydroxylated carotenoid zeaxanthin is produced from preexisting violaxanthin upon exposure to excess light conditions. Zeaxanthin binding to components of the photosystem II (PSII) antenna system has been investigated thoroughly and shown to help in the dissipation of excess chlorophyll-excited states and scavenging of oxygen radicals. However, the functional consequences of the accumulation of the light-harvesting complex I (LHCI) proteins in the photosystem I (PSI) antenna have remained unclarified so far. In this work we investigated the effect of zeaxanthin binding on photoprotection of PSI–LHCI by comparing preparations isolated from wild-type Arabidopsis thaliana (i.e., with violaxanthin) and those isolated from the A . thaliana nonphotochemical quenching 2 mutant, in which violaxanthin is replaced by zeaxanthin. Time-resolved fluorescence measurements showed that zeaxanthin binding leads to a previously unrecognized quenching effect on PSI–LHCI fluorescence. The efficiency of energy transfer from the LHCI moiety of the complex to the PSI reaction center was down-regulated, and an enhanced PSI resistance to photoinhibition was observed both in vitro and in vivo. Thus, zeaxanthin was shown to be effective in inducing dissipative states in PSI, similar to its well-known effect on PSII. We propose that, upon acclimation to high light, PSI–LHCI changes its light-harvesting efficiency by a zeaxanthin-dependent quenching of the absorbed excitation energy, whereas in PSII the stoichiometry of LHC antenna proteins per reaction center is reduced directly.

Astaxanthin is a ketocarotenoid produced by photosynthetic microalgae. It is a pigment of high industrial interest in acquaculture, cosmetics, and nutraceutics due to its strong antioxidant power. Haematococcus pluvialis , a fresh-water microalga, accumulates high levels of astaxanthin upon oxidative stress, reaching values up to 5% per dry weight. H. pluvialis accumulates astaxanthin in oil droplets in the cytoplasm, while the chloroplast volume is reduced. In this work, we investigate the biochemical and spectroscopic properties of the H. pluvialis pigment binding complexes responsible for light harvesting and energy conversion. Our findings demonstrate that the main features of chlorophyll and carotenoid binding complexes previously reported for higher plants or Chlamydomonas reinhardtii are preserved under control conditions. Transition to astaxanthin rich cysts however leads to destabilization of the Photosystems. Surprisingly, astaxanthin was found to be bound to both Photosystem I and II, partially substituting β-carotene, and thus demonstrating possible astaxanthin biosynthesis in the plastids or transport from the cytoplasm to the chloroplast. Astaxanthin binding to Photosystems does not however improve their photoprotection, but rather reduces the efficiency of excitation energy transfer to the reaction centers. We thus propose that astaxanthin binding partially destabilizes Photosystem I and II.

ObjectivesEvaluate evolution of cardiovascular risk (CVR) in a cohort of systemic sclerosis (SSc) in one year of follow-up.MethodsProspective longitudinal study of a cohort of 45 patients with SSc during a period of one year. Sociodemographic and analytical variables were analysed at the time of inclusion in the study (baseline) and after 12 months of follow-up. The vascular protocol with carotid ultrasound was performed, including the determination of carotid intima-media thickness (IMT) and the evaluation of atheromatous plaques; in addition to the performance of the ankle-brachial index (ABI) and the determination of endothelial dysfunction (ED) through the measurement of flow-mediated vasodilation (FMVD), all at baseline and at one year.Results45 patients were included, 94% of them female, with a mean age of 52.2±11.5 years and mean evolution time of 4.6±5.1 years. The distribution by subgroups was 44.4% limited SSc, 35.5% diffuse SSc, 4.4% pre-scleroderma, 4.4% sine scleroderma SSc, 6.6% MTCD, and 4.4% overlap syndrome. Classical CVR variables were collected as smoking habit, DM, HTN, obesity, DLP, hyperhomocysteinemia, and clinical variables of the SSc were added such as modified Rodnan Skin Score (mRSS), pulmonary arterial hypertension (PAH), interstitial lung disease (ILD), capillaroscopic pattern, SSc specific antibodies and previous treatments.A bivariate analysis was performed using binomial logistic regression, both at baseline and at one year. Pathological IMT (>0.9 mm) was significantly associated with hyperhomocysteinemia (p=0.024, OR=3.03, CI 1.33–9.58). The presence of atheromatous plaque was associated with corticosteroid treatment (p=0.048, OR=0.58, CI 0.28–0.97). Pathological ITB (<0.9) was significantly associated with the 25-OH-vitamin D deficit (p=0.031, OR=0.25, CI 0.06–0.77). ED did not show a statistically significant association with the parameters studied.To evaluate the effect of time, a binomial model was adjusted by linear regression of mixed effects for the variables of CV affectation considered (see table 1). Time proved to be a risk factor to present pathological ITB values, since it was evidenced at baseline in 4.4% of the sample compared to 20% in the one-year study. Consequently, a multivariate analysis was performed showing pathological ABI was significantly associated to time (p<0.001, OR=59.7, CI 59.64–59.75) and mRSS, although with little effect (p<0.001, OR=0.042, IC 0.036–0.047). Time was not a risk factor for the appearance of pathological IMT, ED or plaques.Abstract AB0772 – Figure 1ConclusionsIn our study, we observed the significant variation in ABI in one year, this may be due to the fact that this measurement has a high sensitivity for the detection of early peripheral arterial disease, in those patients who have not manifested signs and symptoms of arterial disease due to more evolved time of evolution.AcknowledgementsThank you Casandra Jimenez for her help with the vascular database compilationDisclosure of InterestNone declared

Excitonic solar cells, within which bound electron-hole pairs have a central role in energy harvesting, have represented a hot field of research over the last two decades due to the compelling prospect of low-cost solar energy. However, in such cells, exciton dissociation and charge collection occur with significant losses in energy, essentially due to poor charge screening. Organic–inorganic perovskites show promise for overcoming such limitations. Here, we use optical spectroscopy to estimate the exciton binding energy in the mixed-halide crystal to be in the range of 50 meV. We show that such a value is consistent with almost full ionization of the exciton population under photovoltaic cell operating conditions. However, increasing the total photoexcitation density, excitonic species become dominant, widening the perspective of this material for a host of optoelectronic applications. The performance of perovskite-based solar cells has improved dramatically in recent years, yet surprisingly little is known about the details of how they work. Grancini et al . report results that suggest that their behaviour is dominated by the transport of free carriers rather than excitons.

BackgroundPatients with rheumatic disease, especially if they are under biological therapy, are more likely to suffer infections. Because of that, there are a vaccine recommendations. Nevertheless, the effectiveness of this vaccines is unknown and it seems to be affected by the treatment used.ObjectivesTo asses the response to the Influenza (Influ) virus A and B, and the response to hepatitis B virus (HBV) in patients with biological therapy.MethodsMulticenter study which includes patients with the following guideline:older than 18 years with diagnosis of Rheumatoid arthritis (RA), Spondiloarthritis (SpA), Psoriasic arthritis (PsoA), Psoriasic (Pso), inflammatory intestinal disease (IID), or connectives. All of them coming from hospitals where The Central Laboratory of the Region of Madrid provides services. This patients must be being treated with Infliximab (IFX), Adalimumab (ADA), Etanercept (ETA), Certolizumab (CERTO), Golimumab (GOLI), Tocilizumab (TOCI), Abatacept (ABATA), Rituximab (RTX), Ustekinumab or any other biological therapy, or will iniciate in the period of this study.The response to a flu vaccine was measured by detecting antibody IgG against Influ A and B by ELISA technique at the beginning of the study and at 6 weeks from the vaccination. The same from HBV, it was measured the HbSAb at the beginning and 6 weeks after vaccination. The statistical analysis was made by the statistical system SPSS.ResultsData from 96 patients 63 of which (65.6%) were women with an average age of 48.4±12.8 years and a disease presence for 10.4±19 years. Among all patients, 34/96 (35.4%) were AR, 35/96 (36.5%) SpA, 14/96 (14.6%) A.PSO, 3/96 (3.1%) PSO, 2/96 (2, 1%) IBD, 8/96 (8.3%) other diseases. Biological treatment duration at the time of inclusion was 22.3±21 months. Forty-five (46.8%) and Seventeen (17.7%) had concomitant DMARDs and corticosteroids, respectively. Of the 82 patients treated with DMARDs 75.5% had methotrexate. The biological treatments received were: 9.4% IFX; 31.3% ADA; 25% ETA; CERTO 2.1%; GOLI 11.5%; RTX 12.5%; TOCI 7.3%, 1.04% 1.04% Other Fold.The 52.1% of patients had been vaccinated against influenza the previous year; 54.1% had been previously vaccinated against HBV, 81% of which had received 3 doses. 16/47 of these (34%) had AcHbS>10 at baseline.Antibodies titer was positive from 71.8% and 44.8% for InfluA and InfluB respectively at baseline. After vaccination, 6/96 (6.2%) had seroconverted for Influ A and 4/96 (4.2%) for InfluB. Failed to parse differences in response to flu or HBV among treatments due to the small number of respondents.The rate of adverse effects associated to the administration of vaccines was 7.3% and a infection rate of 2.1% from October to December 2014.ConclusionsThe number of patients completing vaccination according to standard is lower than expected. The response to HBV vaccination in these patients is very low and lower than expected in flu vaccination. More immunogenic vaccines against influenza are needed, and determine HbSAb after completing vaccination to see the necessity of booster or even of a second vaccination cycle in non-responder patients.Disclosure of InterestP. Alcocer Grant/research support from: This project has received funding of Pfizer, SORCOM-MSD grant and has applied for a grant from the European University, M. T. Navio: None declared, M. Maria Dolores: None declared, P. Castro: None declared, J. Yuste: None declared, S. Muñoz-Fernández: None declared

Light-harvesting complexes (LHCs) are major constituents of the antenna systems in higher plant photosystems. Four Lhca subunits are tightly bound to the photosystem I (PSI) core complex, forming its outer antenna moiety called LHCI. The Arabidopsis thaliana mutant ΔLhca lacks all Lhca1–4 subunits and compensates for its decreased antenna size by binding LHCII trimers, the main constituent of the photosystem II antenna system, to PSI. In this work we have investigated the effect of LHCI/LHCII substitution by comparing the light harvesting and excitation energy transfer efficiency properties of PSI complexes isolated from ΔLhca mutants and from the wild type, as well as the consequences for plant growth. We show that the excitation energy transfer efficiency was not compromised by the substitution of LHCI with LHCII but a significant reduction in the absorption cross-section was observed. The absence of LHCI subunits in PSI thus significantly limits light harvesting, even on LHCII binding, inducing, as a consequence, a strong reduction in growth. A quadruple mutant of Arabidopsis lacking all four subunits of light harvesting complex I (LHCI) compensates by binding LHCII complexes to photosystem I instead. This maintained similar excitation energy transfer efficiency but with a much reduced absorption cross-section.

In patients with rheumatoid arthritis (RA), the development of antibodies to infliximab (ATI) is associated with poor clinical response. 1 2-7 Nevertheless, there is no plausible explanation for why not all patients with ATI experience high disease activity. Table 1 Total: 11 patients with RA (%) Gender, female n (%) 11 (100) Age, mean (SD) 54.18±13.24 Autoantibodies: RF positive n (%) 9 (81.8) ACPA positive n (%) 9 (81.8) Disease duration (years), mean (SD) 14.20±6.42 Baseline DAS28, mean (SD) 5.45±1.13 Time under Ifx therapy in years, mean (SD) 8.00±2.75 ATI duration in years, mean (SD) 1.1±0.91 Concomitant treatment MTX alone 3 (27.2) OD 1 (9.0) MTX+OD 6 (54.8) Ifx monotherapy 1 (9.0) ACPA, Anticitrullinated protein antibody; ATI, antibodies to infliximab; DAS28, Disease Activity Score 28; Ifx, infliximab; MTX, Methotrexate; OD, Other DMARDs; RF, Rheumatoid Factor.

Background Biological therapy (BT) is very effective in patients with rheumatoid arthritis (RA). Although there are tools to measure treatment response, they have limitations making necessary to get more objective parameters to improve clinical evaluation. The immunogenicity of anti-TNF therapy has been associated with lack of efficacy, side effects and decreased survival. In our hospital, the monitoring of immunogenicity is considered as an additional tool to clinical practice since 2010, helping in treatment decisions as switching medication, dose reduction or even discontinuation. Objectives To asses the benefit of using the immunogenicity as a complementary tool in clinical practice of RA patients and to analyse differences in outcome measures before and after the use of immunogenicity. Methods We included 134 RA patients who started a 1st biologicbetween the years 2005-2012. The patients were divided into two time periods to analyze differences in clinical management after to monitor the BT immunogenicity: 1st period (1P) from 2005 to 2009 with 89 patients and 2nd period (2P) from 2010 to 2012 with 45 patients. The used drugs were infliximab, adalimumab, etanercept, rituximab, tocilizumab, abatacept and certolizumab. The clinical activity was measured by DAS28 and the clinical improvemet by delta-DAS28. The drug and anti-drug antibodies (ADA) serum levels were measured by ELISA. Statistical analysis was performed using SPSS 11.0. Results A similar control of disease activity is achieved in both periods, but in the 2P, where in addition to the usual measures we use immunogenicity monitoring, shows that we are more cost-effective, taking decisions earlier and more accurate. These data suggest that immunogenicity can help to improve and personalize the clinical manage of patients treated with biologicals. Conclusions A similar control of disease activity is achieved in both periods, but in the 2P, where in addition to the usual measures we use immunogenicity monitoring, shows that we are more cost-effective, taking decisions earlier and more accurate. These data suggest that immunogenicity can help to improve and personalize the clinical manage of patients treated with biologicals. Disclosure of Interest None Declared