289 research outputs found

    Relaxation processes in thiophene-based random copolymers

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    The relaxation dynamics of soluble polyalkylthiophenes obtained by the random copolymerisation of 3,4-dibutylthiophene and 3-butylthiophene monomers is investigated. In these systems, the effective conjugation length, the optical gap and the non-radiative decay rate are controlled by varying the content of disubstituted monomers, the steric hindrance of which induces a twisting angle between thiophene rings. Several indications are reported in favour of spectral diffusion of the photoexcitations. Migration processes mainly occur within a few tens of picoseconds

    A local fingerprint for hydrophobicity and hydrophilicity: from methane to peptides

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    An important characteristic that determines the behavior of a solute in water is whether it is hydrophobic or hydrophilic. The traditional classification is based on chemical experience and heuristics. However, this does not reveal how the local environment modulates this important property. We present a local fingerprint for hydrophobicity and hydrophilicity inspired by the two body contribution to the entropy. This fingerprint is an inexpensive, quantitative and physically meaningful way of studying hydrophilicity and hydrophobicity that only requires as input the water-solute radial distribution functions. We apply our fingerprint to octanol, benzene and the 20 proteinogenic amino acids. Our measure of hydrophilicity is coherent with chemical experience and, moreover, it also shows how the character of an atom can change as its environment is changed. Lastly, we use the fingerprint as collective variable in a funnel metadynamics simulation of a host-guest system. The fingerprint serves as a desolvation collective variable that enhances transitions between the bound and unbound states

    Cerebellocerebral connectivity predicts body mass index: A new open-source Python-based framework for connectome-based predictive modeling

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    Background: The cerebellum is one of the major central nervous structures consistently altered in obesity. Its role in higher cognitive function, parts of which are affected by obesity, is mediated through projections to and from the cerebral cortex. We therefore investigated the relationship between body mass index (BMI) and cerebellocerebral connectivity.Methods: We utilized the Human Connectome Project's Young Adults dataset, including functional magnetic resonance imaging (fMRI) and behavioral data, to perform connectome-based predictive modeling (CPM) restricted to cerebellocerebral connectivity of resting-state fMRI and task-based fMRI. We developed a Python-based open-source framework to perform CPM, a data-driven technique with built-in cross-validation to establish brain-behavior relationships. Significance was assessed with permutation analysis.Results: We found that (i) cerebellocerebral connectivity predicted BMI, (ii) task-general cerebellocerebral connectivity predicted BMI more reliably than resting-state fMRI and individual task-based fMRI separately, (iii) predictive networks derived this way overlapped with established functional brain networks (namely, frontoparietal networks, the somatomotor network, the salience network, and the default mode network), and (iv) we found there was an inverse overlap between networks predictive of BMI and networks predictive of cognitive measures adversely affected by overweight/obesity.Conclusions: Our results suggest obesity-specific alterations in cerebellocerebral connectivity, specifically with regard to task execution. With brain areas and brain networks relevant to task performance implicated, these alterations seem to reflect a neurobiological substrate for task performance adversely affected by obesity

    Efficacy of biofeedback rehabilitation based on visual evoked potentials analysis in patients with advanced age-related macular degeneration

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    Age-related macular degeneration (AMD) is a progressive and degenerative disorder of the macula. In advanced stages, it is characterized by the formation of areas of geographic atrophy or fibrous scars in the central macula, which determines irreversible loss of central vision. These patients can benefit from visual rehabilitation programmes with acoustic "biofeedback" mechanisms that can instruct the patient to move fixation from the central degenerated macular area to an adjacent healthy area, with a reorganization of the primary visual cortex. In this prospective, comparative, non-randomized study we evaluated the efficacy of visual rehabilitation with an innovative acoustic biofeedback training system based on visual evoked potentials (VEP) real-time examination (Retimax Vision Trainer, CSO, Florence), in a series of patients with advanced AMD compared to a control group. Patients undergoing training were subjected to ten consecutive visual training sessions of 10min each, performed twice a week. Patients in the control group did not receive any training. VEP biofeedback rehabilitation seems to improve visual acuity, reading performances, contrast sensitivity, retinal fixation and sensitivity and quality of life in AMD patients

    Cell death and impairment of glucose-stimulated insulin secretion induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the beta-cell line INS-1E.

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    The aim of this research was to characterize 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity on the insulin-secreting beta-cell line INS-1E. A sharp decline of cell survival (below 20%) was observed after 1 h exposure to TCDD concentrations between 12.5 and 25 nM. Ultrastructurally, beta-cell death was characterized by extensive degranulation, appearance of autophagic vacuoles, and peripheral nuclear condensation. Cytotoxic concentrations of TCDD rapidly induced a dose-dependent increase in intracellular calcium concentration. Blocking calcium entry by EGTA significantly decreased TCDD cytotoxicity. TCDD was also able to rapidly induce mitochondrial depolarization. Interestingly, 1 h exposition of INS-1E cells to very low TCDD concentrations (0.05-1 nM) dramatically impaired glucose-stimulated but not KCl-stimulated insulin secretion. In conclusion, our results clearly show that TCDD exerts a direct beta-cell cytotoxic effect at concentrations of 15-25 nM, but also markedly impairs glucose-stimulated insulin secretion at concentrations 20 times lower than these. On the basis of this latter observation we suggest that pancreatic beta-cells could be considered a specific and sensitive target for dioxin toxicity

    Sirolimus as a second-line treatment for Graves’ orbitopathy

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    Objectives: A beneficial effect of sirolimus in Graves’ orbitopathy (GO) was reported, suggesting a possible use in clinical practice. We conducted an observational, single-centre, no-profit, clinical study to investigate the efficacy of sirolimus as a second-line treatment for moderate-to-severe, active GO compared with methylprednisolone. Methods: Data from consecutive patients given sirolimus (2 mg orally on first day, followed by 0.5 mg/day for 12 weeks) or methylprednisolone [500 mg iv/weekly (6 weeks), 250 mg/weekly (6 weeks)] as a second-line treatment were collected and compared. Primary objective: overall GO outcome at 24 weeks, based on a composite evaluation. Secondary objectives at 24 weeks: (1) improvement in quality of life, evaluated using a specific uestionnaire (GO-QoL); (2) reduction in proptosis; (3) reduction in the clinical activity score (CAS); (4) improvement of eye ductions; and (5) reduction in eyelid aperture. Results: Data from 30 patients (15 per group) treated between January 15, 2020, and June 15, 2021, were analysed. Proportion of GO responders (primary outcome) at 24 weeks was significantly greater in sirolimus group compared with methylprednisolone group (86.6% vs 26.6%; OR: 17.8; 95% CI from 2.7 to 116.8; P = 0.0026). GO-quality of life (GO-QoL) score was greater in sirolimus group. Proportion of proptosis responders was greater in sirolimus group, as well as proportion of clinical activity score (CAS) responders. No serious adverse events were observed, with no differences between groups. Conclusions: Sirolimus seems to be an effective second-line treatment for GO. Further randomized clinical trials are needed to confirm our observations

    Electrical double layer and capacitance of TiO2 electrolyte interfaces from first principles simulations

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    The electrical double layer (EDL) at aqueous solution-metal oxide interfaces critically affects many fundamental processes in electrochemistry, geology and biology, yet understanding its microscopic structure is challenging for both theory and experiments. Here we employ ab initio-based machine learning potentials including long-range electrostatics in large-scale atomistic simulations of the EDL at the TiO2-electrolyte interface. Our simulations provide a molecular-scale picture of the EDL that demonstrates the limitations of standard mean-field models. We further develop a method to accurately calculate the electrostatic potential drop at the interface. The computed capacitance originating from the adsorbed charges and the potential drop agrees with experiments, supporting the reliability of our description of the EDL. The larger interfacial capacitance of basic relative to acidic solutions originates from the higher affinity of the cations for the oxide surface and gives rise to distinct charging mechanisms on negative and positive surfaces

    Teaching geriatric medicine through gamification: a tool for enhancing postgraduate education in geriatric medicine

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    Background Polypharmacy is becoming increasingly common and all doctors must be prepared to manage it competently. Aims The aim of this project is to evaluate the feasibility and use of a novel gamification-based teaching intervention on polypharmacy among doctors undergoing advanced geriatric training. Among others, one of the learning goals for the students was to be able to describe the adherence to medication. Methods Electronic questionnaire sent to students of the third session “evidence-based medicine in geriatrics” of advanced postgraduate course in geriatrics of the European Academy for Medicine of Ageing. Results Most students reported issues with forgetting doses and remembering sufficiently to establish a medication routine due to busy schedules as well as social influences around medication taking. Reflecting on the challenges of the game, most students reported that their own prescribing practice was likely to change. Discussion and conclusion The current model of learning appears to be a feasible approach for postgraduate medical education or in other areas of healthcare such as nursing or physiotherapy. Learning through action and reflection promotes deeper thinking and can lead to behavioral change, in this case thus enhancing the attitudes and understanding regarding pharmacological issues associated with ageing. Recommendations for future research in medical education about medication adherence are outlined.publishedVersio
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