Nanoantenna enhanced emission of lightharvesting complex 2: the role of resonance, polarization, and radiative and non-radiative rates

Nanoantennae show potential for photosynthesis research for two reasons; first by spatially confining light for experiments which require high spatial resolution, and second by enhancing the photon emission of single light-harvesting complexes. For effective use of nanoantennae a detailed understanding of the interaction between the nanoantenna and the light-harvesting complex is required. Here we report how the excitation and emission of multiple purple bacterial LH2s (light-harvesting complex 2) are controlled by single gold nanorod antennae. LH2 complexes were chemically attached to such antennae, and the antenna length was systematically varied to tune the resonance with respect to the LH2 absorption and emission. There are three main findings. (i) The polarization of the LH2 emission is fully controlled by the resonant nanoantenna. (ii) The largest fluorescence enhancement, of 23 times, is reached for excitation with light at λ = 850 nm, polarized along the long antenna-axis of the resonant antenna. The excitation enhancement is found to be 6 times, while the emission efficiency is increased 3.6 times. (iii) The fluorescence lifetime of LH2 depends strongly on the antenna length, with shortest lifetimes of [similar]40 ps for the resonant antenna. The lifetime shortening arises from an 11 times resonant enhancement of the radiative rate, together with a 2–3 times increase of the non-radiative rate, compared to the off-resonant antenna. The observed length dependence of radiative and non-radiative rate enhancement is in good agreement with simulations. Overall this work gives a complete picture of how the excitation and emission of multi-pigment light-harvesting complexes are influenced by a dipole nanoantenna.

The Barcelona Forum: on decentralized governance and conflict prevention 6-8 july 2009

The Barcelona Forum aimed to generate both a theoretical and practical discussion on decentralized governance and its capacity to promote peace, prevent conflict, advance human security and ensure greater governmental accountability. The Forum intended to review the theoretical strength of decentralization as a political tool and discuss how it can be properly implemented. Eight case studies were selected to be covered during the two days in order to draw conclusions and offer proposals for the future implementation of decentralization. The case of Catalonia and the decentralized experience of Spain was given special attention, as an example of successful decentralization. The other cases presented achievements and challenges and prompted discussions on both the validity and universality of decentralization as a way to promote and preserve peace. Topics such as ethnic and territorial divisions, democratic accountability, financial decentralization and distribution, resource sharing, and external implementation of decentralization through peace processes were discussed.

Papel de la Interleucina 6 (IL-6) en la regulación de la expresión de Osteopontina (OPN) y CD44 tras axotomía del nervio facial

Investigación producida a partir de una estancia en la University of Sidney, Australia, entre octubre del 2008 y enero del 2009. Se ha desarrollado el proyecto titulado "Papel de la interleucina 6 (IL6) en la regulación de la expresión de Osteopontina (OPN) y de CD44 tras axotomía del nervio facial". Tras efectuar una transección del nervio facial, se indujo una reactividad glial en el núcleo facial (NF) localizado en el tronco cerebral, utilizando ratones transgénicos que sobrexpresan IL6 bajo promotor GFAP (tg GFAP-IL6), es decir selectivamente en astrocitos. Se han utilizado técnicas histoquímicas e inmunohistoquímicas, así como también se ha completado el estudio utilizando análisis de RPA, western blotting y citometría de flujo para la identificación de poblaciones celulares. Los resultados obtenidos indican que la OPN se expresa constitutivamente en las neuronas del NF. Tras axotomía del nervio facial, la expresión de OPN y CD44 incrementa en los ratones WT, mientras que en los tg GFAP-IL6 disminuye significativamente, sugiriendo que la IL6 podría estar involucrada en la modulación de la expresión de ambas moléculas. Sin embargo, no se ha visto diferencias en otros receptores de OPN como la integrina Alpha-5. La ctometría de flujo corroboró algunos de los resultados histológicos sobre la reactividad microglial y permitió concluir que la proporción de microglía activada (CD11b+/CD45+mid) y macrófagos (CD11b+/CD45+high) que expresan CD44 incrementa en in los tg GFAP-IL6 versus WT donde la mayor parte de microglia activada mostraba un perfil CD11b+/CD45+low.

Efectes de les separacions o divorcis en el rendiment acadèmic dels alumnes de 5è i 6è d’una escola local

Aquest Treball Final de Grau aporta els resultats d’un estudi sobre els efectes i condicionats que suposa pel rendiment acadèmic dels alumnes de cicle superior de primària el divorci o la separació dels seus progenitors. Ens trobem davant l’augment del nombre de trencaments familiars, que ha esdevingut un fenomen clarament observable en la societat, es tracta d’un fenomen complex, en el qual entren en joc nombroses variables. I el trencament també suposa conseqüències socials, en primer lloc, pels fills/es. En una primera part ens endinsem en les aportacions i teories que han defensat diversos experts al llarg del temps sobre aquest fet. En una segona part es presenten les conclusions i els acords extrets de diverses entrevistes amb mestres d’una escola local en relació a la possible vinculació entre trencament familiar i rendiment acadèmic. I, per últim, s’acaben comparat les visions dels autors teòrics amb les aportacions i visions dels educadors professionals; per arribar a les principals conclusions que, no es pot generalitzar els efectes negatius de la ruptura, cal veure també les possibilitats positives del moment i, per últim, destacar que la manera amb la qual la família s'afronta a la ruptura té una importància crucial a l'hora de determinar l'impacte d'aquesta la ruptura en els fills.

Dietary n-6- or n-3-rich vegetable fats and antioxidants: effects on fatty acid composition and stability of rabbit plasma, liver and meat

We supplemented diets with a-tocopheryl acetate (100 mg/kg) and replaced beef tallow (BT) in feeds with increasing doses of n-6- or n-3-rich vegetable fat sources (linseed and sunflower oil), and studied the effects on the fatty acid (FA) composition, the a-tocopherol (aT) content and the oxidative stability of rabbit plasma and liver. These effects were compared with those observed in a previous study in rabbit meat. As in meat, the content of saturated, monounsaturated and trans FA in plasma and liver mainly reflected feed FA profile, except stearic acid in liver, which increased as feeds contained higher doses of vegetable fat, which could be related to an inhibition of the activity of the stearoyl-CoA-desaturase. As linseed oil increased in feeds, the n-6/n-3 FA ratio was decreased in plasma and liver as a result of the incorporation of FA from diets and also, due to the different performance and selectivity of desaturase enzymes. However, an increase in the dose of vegetable fat in feeds led to a significant reduction in the aT content of plasma and liver, which was greater when the fat source was linseed oil. Increasing the dose of vegetable fat in feeds also led to an increase in the susceptibility to oxidation (lipid hydroperoxide (LHP) value) of rabbit plasma, liver and meat and on the thiobarbituric acid (TBA) values of meat. Although the dietary supplementation with a-tocopheryl acetate increased the aT content in plasma and liver, it did not modify significantly their TBA or LHP values. In meat however, both TBA and LHP values were reduced by the dietary supplementation with a-tocopheryl acetate. The plasma aT content reflected the aT content in tissues, and correlated negatively with tissue oxidability. From the studied diets, those containing 1.5% linseed oil plus 1.5% BT and 100 mg of a-tocopheryl acetate/kg most improved the FA composition and the oxidative stability of rabbit tissues.

Pd-catalysed amidation of 2,6-dihalopurine nucleosides. Replacement of iodine at 0 ºC

Pd-catalysed reactions of 2-Cl, 2-Br and 2-I derivatives of a 6-chloropurine nucleoside with benzamide have been compared, using Pd2dba3, Xantphos and Cs2CO3 in toluene, between 20 and 80 °C. The reactivity order was 2-I > 2-Br > 6-Cl ≫ 2-Cl. The 2-I substituent could be replaced even at 0 °C, under conditions disclosed here for the first time. On the other hand, the replacement of the chlorine atom at position 2 (2-Cl) required 110 °C.

The Smc5/6 complex is required for dissolution of DNA-mediated sister chromatid linkages

Mitotic chromosome segregation requires the removal of physical connections between sister chromatids. In addition to cohesin and topological entrapments, sister chromatid separation can be prevented by the presence of chromosome junctions or ongoing DNA replication. We will collectively refer to them as DNA-mediated linkages. Although this type of structures has been documented in different DNA replication and repair mutants, there is no known essential mechanism ensuring their timely removal before mitosis. Here, we show that the dissolution of these connections is an active process that requires the Smc5/6 complex, together with Mms21, its associated SUMO-ligase. Failure to remove DNA-mediated linkages causes gross chromosome missegregation in anaphase. Moreover, we show that Smc5/6 is capable to dissolve them in metaphase-arrested cells, thus restoring chromosome resolution and segregation. We propose that Smc5/6 has an essential role in the removal of DNA-mediated linkages to prevent chromosome missegregation and aneuploidy.

A Be-type star with a black-hole companion

Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen). Of the ~80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as companions. A black hole was formally allowed as a solution for the companion to the Be star MWC 656 (also known as HD 215227), although that was based on a single radial velocity curve of the Be star, a mistaken spectral classification and rough estimates of the inclination angle. Here we report observations of an accretion disk line mirroring the orbit of the Be star. This, together with an improved radial velocity curve of the Be star through fitting sharp Fe II profiles from the equatorial disk, and a refined Be classification (to that of a B1.5-B2 III star), reveals a black hole of 3.8 to 6.9 solar masses orbiting MWC 656, the candidate counterpart of the gamma-ray source AGL J2241+4454. The black hole is X-ray quiescent and fed by a radiatively inefficient accretion flow giving a luminosity less than 1.6 x 10-7 times the Eddington luminosity. This implies that Be binaries with black-hole companions are difficult to detect by conventional X-ray surveys.

Pd-catalysed amidation of 2,6-dihalopurine nucleosides. Replacement of iodine at 0 ºC

Pd-catalysed reactions of 2-Cl, 2-Br and 2-I derivatives of a 6-chloropurine nucleoside with benzamide have been compared, using Pd2dba3, Xantphos and Cs2CO3 in toluene, between 20 and 80 °C. The reactivity order was 2-I > 2-Br > 6-Cl ≫ 2-Cl. The 2-I substituent could be replaced even at 0 °C, under conditions disclosed here for the first time. On the other hand, the replacement of the chlorine atom at position 2 (2-Cl) required 110 °C.

Aplicación de un programa integral de actividad física en niños y niñas entre 6 y 12 años con sobrepeso y obesidad

El propósito de este estudio longitudinal prospectivo es abordar un plan integral de actividad física en niños y niñas entre 6 y 12 años que padezcan sobrepeso y obesidad. El programa se llevará a cabo en el Hospital de San Juan de Dios de Barcelona, donde se utilizarán una serie de variables de medida y tests que serán valorados antes, durante y después de este plan integral. Participarán dos profesionales de la salud, un fisioterapeuta y un nutricionista, quienes intervendrán en 20 niños y niñas con sobrepeso y obesidad. La finalidad de este estudio es disminuir el índice de masa corporal (IMC), así como el porcentaje de grasa corporal total (GCT) en los niños y niñas con sobrepeso y obesidad. También se pretende introducir y fomentar hábitos de vida saludables en relación a la actividad física y la alimentación en los niños y niñas y en su entorno familiar.

Cyclin-dependent kinases 4 and 6 control tumor progression and direct glucose oxidation in the pentose cycle

Cyclin-dependent kinases CDK4 and CDK6 are essential for the control of the cell cycle through the G1 phase. Aberrant expression of CDK4 and CDK6 is a hall- mark of cancer, which would suggest that CDK4 and CDK6 are attractive targets for cancer therapy. Herein, we report that calcein AM is a potent specific inhibitor of CDK4 and CDK6 in HCT116 human colon adenocarcinoma cells, inhibiting retinoblastoma protein (pRb) phosphorylation and inducing cell cycle arrest in the G1 phase. The metabolic effects of calcein AM (the calcein acetoxymethyl-ester) on HCT116 cells were also evaluated and the flux between the oxidative and non-oxidative branches of the pentose phos-phate pathway was significantly altered. To elucidate whe-ther these metabolic changes were due to the inhibition of CDK4 and CDK6, we also characterized the metabolic profile of a CDK4, CDK6 and CDK2 triple knockout of mouse embryonic fibroblasts. The results show that the metabolic profile associated with the depletion of CDK4, CDK6 and CDK2 coincides with the metabolic changes induced by calcein AM on HCT116 cells, thus confirming that the inhibition of CDK4 and CDK6 disrupts the balance between the oxidative and non-oxidative branches of the pentose phosphate pathway. Taken together, these results indicate that low doses of calcein can halt cell division and kill tumor cells. Thus, selective inhibition of CDK4 and CDK6 may be of greater pharmacological interest, since inhibitors of these kinases affect both cell cycle progression and the robust metabolic profile of tumors.

Predictors of remission in the treatment of major depressive disorder: real-world evidence from a 6-month prospective observational study

BACKGROUND: This study examined potential predictors of remission among patients treated for major depressive disorder (MDD) in a naturalistic clinical setting, mostly in the Middle East, East Asia, and Mexico. METHODS: Data for this post hoc analysis were taken from a 6-month prospective, noninterventional, observational study that involved 1,549 MDD patients without sexual dysfunction at baseline in 12 countries worldwide. Depression severity was measured using the Clinical Global Impression of Severity and the 16-item Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR16). Depression-related pain was measured using the pain-related items of the Somatic Symptom Inventory. Remission was defined as a QIDS-SR16 score ≤5. Generalized estimating equation regression models were used to examine baseline factors associated with remission during follow-up. RESULTS: Being from East Asia (odds ratio [OR] 0.48 versus Mexico; P<0.001), a higher level of depression severity at baseline (OR 0.77, P=0.003, for Clinical Global Impression of Severity; OR 0.92, P<0.001, for QIDS-SR16), more previous MDD episodes (OR 0.92, P=0.007), previous treatments/therapies for depression (OR 0.78, P=0.030), and having any significant psychiatric and medical comorbidity at baseline (OR 0.60, P<0.001) were negatively associated with remission, whereas being male (OR 1.29, P=0.026) and treatment with duloxetine (OR 2.38 versus selective serotonin reuptake inhibitors, P<0.001) were positively associated with remission. However, the association between Somatic Symptom Inventory pain scores and remission no longer appeared to be significant in this multiple regression (P=0.580), (P=0.008 in descriptive statistics), although it remained significant in a subgroup of patients treated with selective serotonin reuptake inhibitors (OR 0.97, P=0.023), but not in those treated with duloxetine (P=0.182). CONCLUSION: These findings are largely consistent with previous reports from the USA and Europe. They also highlight the potential mediating role of treatment with duloxetine on the negative relationship between depression-related pain and outcomes of depression.

Micro- and nanostructuring of poly(ethylene-2,6-naphthalate) surfaces, for biomedical applications, using polymer replication techniques

Here we investigate the formation of superficial micro- and nanostructures in poly(ethylene-2,6-naphthalate) (PEN), with a view to their use in biomedical device applications, and compare its performance with a polymer commonly used for the fabrication of these devices, poly(methyl methacrylate) (PMMA). The PEN is found to replicate both micro- and nanostructures in its surface, albeit requiring more forceful replication conditions than PMMA, producing a slight increase in surface hydrophilicity. This ability to form micro/nanostructures, allied to biocompatibility and good optical transparency, suggests that PEN could be a useful material for production of, or for incorporation into, transparent devices for biomedical applications. Such devices will be able to be autoclaved, due to the polymer's high temperature stability, and will be useful for applications where forceful experimental conditions are required, due to a superior chemical resistance over PMMA.