Emotional modulation of visual cortex activity: A functional nearinfrared spectroscopy study

Functional neuroimaging and electroencephalography reveal emotional effects in early visual cortex. Here, we used fNIRS to examine haemodynamic responses evoked by neutral, positive and negative emotional pictures, matched for brightness, contrast, hue, saturation, spatial frequency and entropy. Emotion content modulated amplitude and latency of oxy-, deoxy- and total haemoglobin response peaks, and induced peripheral autonomic reactions. The processing of positive and negative pictures enhanced haemodynamic response amplitude, and this effect was paralleled by blood pressure changes. The processing of positive pictures was reflected in reduced haemodynamic response peak latency. Together these data suggest early visual cortex holds amplitude-dependent representation of stimulus salience and latency-dependent information regarding stimulus valence, providing new insight into affective interaction with sensory processing

Acute tryptophan depletion attenuates conscious appraisal of social emotional signals in healthy female volunteers

Rationale: Acute tryptophan depletion (ATD) decreases levels of central serotonin. ATD thus enables the cognitive effects of serotonin to be studied, with implications for the understanding of psychiatric conditions, including depression. Objective: To determine the role of serotonin in conscious (explicit) and unconscious/incidental processing of emotional information. Materials and methods: A randomized, double-blind, cross-over design was used with 15 healthy female participants. Subjective mood was recorded at baseline and after 4 h, when participants performed an explicit emotional face processing task, and a task eliciting unconscious processing of emotionally aversive and neutral images presented subliminally using backward masking. Results: ATD was associated with a robust reduction in plasma tryptophan at 4 h but had no effect on mood or autonomic physiology. ATD was associated with significantly lower attractiveness ratings for happy faces and attenuation of intensity/arousal ratings of angry faces. ATD also reduced overall reaction times on the unconscious perception task, but there was no interaction with emotional content of masked stimuli. ATD did not affect breakthrough perception (accuracy in identification) of masked images. Conclusions: ATD attenuates the attractiveness of positive faces and the negative intensity of threatening faces, suggesting that serotonin contributes specifically to the appraisal of the social salience of both positive and negative salient social emotional cues. We found no evidence that serotonin affects unconscious processing of negative emotional stimuli. These novel findings implicate serotonin in conscious aspects of active social and behavioural engagement and extend knowledge regarding the effects of ATD on emotional perception

Fear from the heart: sensitivity to fear stimuli depends on individual heartbeats

Cognitions and emotions can be influenced by bodily physiology. Here, we investigated whether the processing of brief fear stimuli is selectively gated by their timing in relation to individual heartbeats. Emotional and neutral faces were presented to human volunteers at cardiac systole, when ejection of blood from the heart causes arterial baroreceptors to signal centrally the strength and timing of each heartbeat, and at diastole, the period between heartbeats when baroreceptors are quiescent. Participants performed behavioral and neuroimaging tasks to determine whether these interoceptive signals influence the detection of emotional stimuli at the threshold of conscious awareness and alter judgments of emotionality of fearful and neutral faces. Our results show that fearful faces were detected more easily and were rated as more intense at systole than at diastole. Correspondingly, amygdala responses were greater to fearful faces presented at systole relative to diastole. These novel findings highlight a major channel by which short-term interoceptive fluctuations enhance perceptual and evaluative processes specifically related to the processing of fear and threat and counter the view that baroreceptor afferent signaling is always inhibitory to sensory perception

Selective targeting of proteins by hybrid polyoxometalates: Interaction between a bis-biotinylated hybrid conjugate and avidin

The Keggin-type polyoxometalate [\u3b3-SiW10O36]8 12 was covalently modified to obtain a bis-biotinylated conjugate able to bind avidin. Spectroscopic studies such as UV-vis, fluorimetry, circular dichroism, coupled to surface plasmon resonance technique were used to highlight the unique interplay of supramolecular interactions between the homotetrameric protein and the bis-functionalized polyanion. In particular, the dual recognition mechanism of the avidin encompasses (i) a complementary electrostatic association between the anionic surface of the polyoxotungstate and each positively charged avidin subunit and (ii) specific host-guest interactions between each biotinylated arm and a corresponding pocket on the tetramer subunits. The assembly exhibits peroxidase-like reactivity and it was used in aqueous solution for L-methionine methyl ester oxidation by H2O2. The recognition phenomenon was then exploited for the preparation of layer-by-layer films, whose structural evolution was monitored in situ by ATR-FTIR spectroscopy. Finally, cell tracking studies were performed by exploiting the specific interactions with a labeled streptavidin

Higher order Laguerre-Gauss mode degeneracy in realistic, high finesse cavities

Higher order Laguerre-Gauss (LG) beams have been proposed for use in future gravitational wave detectors, such as upgrades to the Advanced LIGO detectors and the Einstein Telescope, for their potential to reduce the effects of the thermal noise of the test masses. This paper details the theoretical analysis and simulation work carried out to investigate the behaviour of LG beams in realistic optical setups, in particular the coupling between different LG modes in a linear cavity. We present a new analytical approximation to compute the coupling between modes, using Zernike polynomials to describe mirror surface distortions. We apply this method in a study of the behaviour of the LG33 mode within realistic arm cavities, using measured mirror surface maps from the Advanced LIGO project. We show mode distortions that can be expected to arise due to the degeneracy of higher order spatial modes within such cavities and relate this to the theoretical analysis. Finally we identify the mirror distortions which cause significant coupling from the LG33 mode into other order 9 modes and derive requirements for the mirror surfaces.Comment: 12 pages Submitted to PRD 19/07/201

Subdynamics as a mechanism for objective description

The relationship between microsystems and macrosystems is considered in the context of quantum field formulation of statistical mechanics: it is argued that problems on foundations of quantum mechanics can be solved relying on this relationship. This discussion requires some improvement of non-equilibrium statistical mechanics that is briefly presented.Comment: latex, 15 pages. Paper submitted to Proc. Conference "Mysteries, Puzzles And Paradoxes In Quantum Mechanics, Workshop on Entanglement And Decoherence, Palazzo Feltrinelli, Gargnano, Garda Lake, Italy, 20-25 September, 199

Quantum theory: the role of microsystems and macrosystems

We stress the notion of statistical experiment, which is mandatory for quantum mechanics, and recall Ludwig's foundation of quantum mechanics, which provides the most general framework to deal with statistical experiments giving evidence for particles. In this approach particles appear as interaction carriers between preparation and registration apparatuses. We further briefly point out the more modern and versatile formalism of quantum theory, stressing the relevance of probabilistic concepts in its formulation. At last we discuss the role of macrosystems, focusing on quantum field theory for their description and introducing for them objective state parameters.Comment: 12 pages. For special issue of J.Phys.A, "The Quantum Universe", on the occasion of 70th birthday of Professor Giancarlo Ghirard

Bioresorbable ureteral stents from natural origin polymers

In this work, stents were produced from natural originpolysaccharides. Alginate, gellan gum, and a blend ofthese with gelatin were used to produce hollow tube (stents)following a combination of templated gelation and criticalpoint carbon dioxide drying. Morphological analysis of thesurface of the stents was carried out by scanning electronmicroscopy. Indwelling time, encrustation, and stability ofthe stents in artificial urine solution was carried out up to 60days of immersion. In vitro studies carried out with simulatedurine demonstrated that the tubes present a high fluid uptakeability, about 1000%. Despite this, the materials are able tomaintain their shape and do not present an extensive swellingbehavior. The bioresorption profile was observed to behighly dependent on the composition of the stent and it canbe tuned. Complete dissolution of the materials may occurbetween 14 and 60 days. Additionally, no encrustation wasobserved within the tested timeframe. The ability to resistbacterial adherence was evaluated with Gram-positive Staphylococcus aureus and two Gram-negatives Escherichia coliDH5 alpha and Klebsiella oxytoca. For K. oxytoca, no differenceswere observed in comparison with a commercialstent (BiosoftVR duo, Porges), although, for S. aureus alltested compositions had a higher inhibition of bacterialadhesion compared to the commercial stents. In case ofE. coli, the addition of gelatin to the formulations reducedthe bacterial adhesion in a highly significant manner comparedto the commercial stents. The stents produced by thedeveloped technology fulfill the requirements for ureteralstents and will contribute in the development of biocompatible and bioresorbable urinary stents.Contract grant sponsor: the European Union Seventh Framework Programme (FP7/2007-2013); contract grant number: REGPOT-CT2012-316331POLARIS Contract grant sponsor: Novel smart and biomimetic materials for innovative regenerative medicine approaches”; contract grant number: RL1 – ABMR – NORTE-01-0124-FEDER-000016; North Portugal Regional Operational Programme (ON.2 – O Novo Norte), National Strategic Reference Framework (NSRF), European Regional Development Fund (ERDF) Contract grant sponsor: FCT post-doc; contract grant numbers: SFRH/BPD/39333/2007, SFRH/BPD/90533/20

Genome size and ploidy of Paracoccidioides brasiliensis reveals a haploid DNA content: Flow cytometry and GP43 sequence analysis

The aim of this study was to evaluate genome size and ploidy of the dimorphic pathogenic fungus Paracoccidioides brasiliensis. The cell cycle analysis of 10 P. brasiliensis isolates by flow cytometry (FCM) revealed a genome size ranging from 26.3+/-0.1Mb (26.9+/-0.1fg) to 35.5+/-0.2Mb (36.3+/-0.2fg) per uninucleated yeast cell. The DNA content of conidia from P. brasiliensis ATCC 60855-30.2+/-0.8Mb (30.9+/-0.8fg) -showed no significant differences with the yeast form, possibly excluding the occurrence of ploidy shift during morphogenesis. The ploidy of several P. brasiliensis isolates was assessed by comparing genome sizing by FCM with the previously described average haploid size obtained from electrophoretic karyotyping. The analysis of intra-individual variability of a highly polymorphic P. brasiliensis gene, GP43, indicated that only one allele seems to be present. Overall, the results showed that all analysed isolates presented a haploid, or at least aneuploid, DNA content and no association was detected between genome size/ploidy and the clinical-epidemiological features of the studied isolates. This work provides new knowledge on P. brasiliensis genetics/genomics, important for future research in basic cellular/molecular mechanisms and for the development/design of molecular techniques in this fungus

Incoherent dynamics in neutron-matter interaction

Coherent and incoherent neutron-matter interaction is studied inside a recently introduced approach to subdynamics of a macrosystem. The equation describing the interaction is of the Lindblad type and using the Fermi pseudopotential we show that the commutator term is an optical potential leading to well-known relations in neutron optics. The other terms, usually ignored in optical descriptions and linked to the dynamic structure function of the medium, give an incoherent contribution to the dynamics, which keeps diffuse scattering and attenuation of the coherent beam into account, thus warranting fulfilment of the optical theorem. The relevance of this analysis to experiments in neutron interferometry is briefly discussed.Comment: 15 pages, revtex, no figures, to appear in Phys. Rev.