Charge separation in an acceptor–donor–acceptor triad material with a lamellar structure

Linking covalently both electron donor and acceptor components is an efficient way to gain thermodynamic control over the formation of well-ordered heterojunction materials suitable for organic photovoltaics. In this context, we attached flexible polymer segments to the termini of a (perylene bisimide)–quaterthiophene–(perylene bisimide) triad. The microphase segregation of the resulting coil-rod-coil architecture served to reliably promote the formation of lamellar phases. The lamellae were oriented vertically relative to the substrate, and they could be laterally aligned by mechanical rubbing, as determined by small and wide angle X-ray scattering, transmission electron microscopy, electron diffraction and AFM. Transient absorption spectroscopy revealed that light absorption was followed by charge separation and that charge recombination was slower in thin films than for solution-phase samples, especially when longer side chains were used. Thus, this study is a first step towards reliable lamellar phase segregation in donor–acceptor materials on the route towards improved materials for organic photovoltaics

Hubble and Spitzer Observations of an Edge-on Circumstellar Disk around a Brown Dwarf

We present observations of a circumstellar disk that is inclined close to edge-on around a young brown dwarf in the Taurus star-forming region. Using data obtained with SpeX at the NASA Infrared Telescope Facility, we find that the slope of the 0.8-2.5 um spectrum of the brown dwarf 2MASS J04381486+2611399 cannot be reproduced with a photosphere reddened by normal extinction. Instead, the slope is consistent with scattered light, indicating that circumstellar material is occulting the brown dwarf. By combining the SpeX data with mid-IR photometry and spectroscopy from the Spitzer Space Telescope and previously published millimeter data from Scholz and coworkers, we construct the spectral energy distribution for 2MASS J04381486+2611399 and model it in terms of a young brown dwarf surrounded by an irradiated accretion disk. The presence of both silicate absorption at 10 um and silicate emission at 11 um constrains the inclination of the disk to be ~70 deg, i.e. ~20 deg from edge-on. Additional evidence of the high inclination of this disk is provided by our detection of asymmetric bipolar extended emission surrounding 2MASS J04381486+2611399 in high-resolution optical images obtained with the Hubble Space Telescope. According to our modeling for the SED and images of this system, the disk contains a large inner hole that is indicative of a transition disk (R_in~58 R_star~0.275 AU) and is somewhat larger than expected from embryo ejection models (R_out=20-40 AU vs. R_out<10-20 AU).Comment: The Astrophysical Journal, in pres

Single-objective high-resolution confocal light sheet fluorescence microscopy for standard biological sample geometries

Three-dimensional fluorescence-based imaging of living cells and organisms requires the sample to be exposed to substantial excitation illumination energy, typically causing phototoxicity and photobleaching. Light sheet fluorescence microscopy dramatically reduces phototoxicity, yet most implementations are limited to objective lenses with low numerical aperture and particular sample geometries that are built for specific biological systems. To overcome these limitations, we developed a single-objective light sheet fluorescence system for biological imaging based on axial plane optical microscopy and digital confocal slit detection, using either Bessel or Gaussian beam shapes. Compared to spinning disk confocal microscopy, this system displays similar optical resolution, but a significantly reduced photobleaching at the same signal level. This single-objective light sheet technique is built as an add-on module for standard research microscopes and the technique is compatible with high-numerical aperture oil immersion objectives and standard samples mounted on coverslips. We demonstrate the performance of this technique by imaging three-dimensional dynamic processes, including bacterial biofilm dispersal, the response of biofilms to osmotic shocks, and macrophage phagocytosis of bacterial cells

Metabolomics analysis of antiquitin deficiency in cultured human cells and plasma: Relevance to pyridoxine-dependent epilepsy

Deficiency of antiquitin (α-aminoadipic semialdehyde dehydrogenase), an enzyme involved in lysine degradation and encoded by ALDH7A1, is the major cause of vitamin B6-dependent epilepsy (PDE-ALDH7A1). Despite seizure control with high dose pyridoxine (PN), developmental delay still occurs in approximately 70% of patients. We aimed to investigate metabolic perturbations due to possible previously unidentified roles of antiquitin, which may contribute to developmental delay, as well as metabolic effects of high dose pyridoxine supplementation reflecting the high doses used for seizure control in patients with PDE-ALDH7A1. Untargeted metabolomics by high resolution mass spectrometry (HRMS) was used to analyze plasma of patients with PDE-ALDH7A1 and two independently generated lines of cultured ReNcell CX human neuronal progenitor cells (NPCs) with CRISPR/Cas mediated antiquitin deficiency. Accumulation of lysine pathway metabolites in antiquitin-deficient NPCs and western-blot analysis confirmed knockdown of ALDH7A1. Metabolomics analysis of antiquitin-deficient NPCs in conditions of lysine restriction and PN supplementation identified changes in metabolites related to the transmethylation and transsulfuration pathways and osmolytes, indicating a possible unrecognized role of antiquitin outside the lysine degradation pathway. Analysis of plasma samples of PN treated patients with PDE-ALDH7A1 and antiquitin-deficient NPCs cultured in conditions comparable to the patient plasma samples demonstrated perturbation of metabolites of the gamma-glutamyl cycle, suggesting potential oxidative stress-related effects in PN-treated patients with PDE-ALDH7A1. We postulate that a model of human NPCs with CRISPR/Cas mediated antiquitin deficiency is well suited to characterize previously unreported roles of antiquitin, relevant to this most prevalent form of pyridoxine-dependent epilepsy

Practice-induced functional plasticity in inhibitory control interacts with aging

Inhibitory control deficits represent a key aspect of the cognitive declines associated with aging. Practicing inhibitory control has thus been advanced as a potential approach to compensate for age-induced neurocognitive impairments. Yet, the functional brain changes associated with practicing inhibitory control tasks in older adults and whether they differ from those observed in young populations remains unresolved.We compared electrical neuroimaging analyses of ERPs recorded during a Go/NoGo practice session with a Group (Young; Older adults) by Session (Beginning; End of the practice) design to identify whether the practice of an inhibition task in older adults reinforces already implemented compensatory activity or reduce it by enhancing the functioning of the brain networks primarily involved in the tasks.We observed an equivalent small effect of practice on performance in the two age-groups. The topographic ERP analyses and source estimations revealed qualitatively different effects of the practice over the N2 and P3 ERP components, respectively driven by a decrease in supplementary motor area activity and an increase in left ventrolateral prefrontal activity in the older but not in the young adults with practice.Our results thus indicate that inhibition task practice in older adults increases age-related divergences in the underlying functional processes

Practice-induced functional plasticity in inhibitory control interacts with aging.

Inhibitory control deficits represent a key aspect of the cognitive declines associated with aging. Practicing inhibitory control has thus been advanced as a potential approach to compensate for age-induced neurocognitive impairments. Yet, the functional brain changes associated with practicing inhibitory control tasks in older adults and whether they differ from those observed in young populations remains unresolved. We compared electrical neuroimaging analyses of ERPs recorded during a Go/NoGo practice session with a Group (Young; Older adults) by Session (Beginning; End of the practice) design to identify whether the practice of an inhibition task in older adults reinforces already implemented compensatory activity or reduce it by enhancing the functioning of the brain networks primarily involved in the tasks. We observed an equivalent small effect of practice on performance in the two age-groups. The topographic ERP analyses and source estimations revealed qualitatively different effects of the practice over the N2 and P3 ERP components, respectively driven by a decrease in supplementary motor area activity and an increase in left ventrolateral prefrontal activity in the older but not in the young adults with practice. Our results thus indicate that inhibition task practice in older adults increases age-related divergences in the underlying functional processes

Data release 2 of S-PLUS : accurate template-fitting based photometry covering ∼1000 deg2 in 12 optical filters

The Southern Photometric Local Universe Survey (S-PLUS) is an ongoing survey of ∼9300 deg2 in the southern sky in a 12-band photometric system. This paper presents the second data release (DR2) of S-PLUS, consisting of 514 tiles covering an area of 950 deg2. The data has been fully calibrated using a new photometric calibration technique suitable for the new generation of wide-field multifilter surveys. This technique consists of a χ2 minimization to fit synthetic stellar templates to already calibrated data from other surveys, eliminating the need for standard stars and reducing the survey duration by ∼15 per cent. We compare the template-predicted and S-PLUS instrumental magnitudesto derive the photometric zero-points(ZPs). We show that these ZPs can be further refined by fitting the stellar templates to the 12 S-PLUS magnitudes, which better constrain the models by adding the narrow-band information. We use the STRIPE82 region to estimate ZP errors, which are 10 mmags for filters J0410, J0430, g,J0515, r,J0660, i,J0861 and z; 15 mmags for filterJ0378; and 25 mmagsfor filters u and J0395. We describe the complete data flow of the S-PLUS/DR2 from observations to the final catalogues and present a brief characterization of the data. We show that, for a minimum signal-to-noise threshold of 5, the photometric depths of the DR2 range from 19.1 to 20.5 mag (measured in Petrosian apertures), depending on the filter. The S-PLUS DR2 can be accessed from the website: https://splus.cloud

Histological Evaluation of Direct Pulp Capping with Silk Sericin: A Preliminary Animal Study

Introduction: This histological study analyzed silk sericin as a potential direct pulp capping biomaterial in contact with pulp and comparing its response to calcium hydroxide. Methods and Materials: Twenty maxillary first molars from Wistar male rats were used, with 60 days of age, between 200 and 300 gr, which were divided in 4 groups (n=5): G1 and G3, controls, capped with calcium hydroxide in 7 and 30 days, respectively; G2 and G4, capped with silk sericin in 7 and 30 days, respectively. Circular cavities were prepared for pulp exposure, where capping materials were applied, being posteriorly restored with glass ionomer cement. After completion of each observation period, the animals were sacrificed and molars were histologically processed for analysis in light microscopy to evaluate presence of necrosis in pulp tissue, inflammatory cells infiltration and tertiary dentin formation. Data analysis was carried out using Kruskal-Wallis and Dunn’s post hoc tests. Results: After 7 days, there was less necrosis and inflammatory cells infiltration in G1 when compared to G2 (P=0.007 and P=0.008, respectively). After 30 days, a sample of G3 induced tertiary dentin formation and G4 showed decrease in inflammation (P=0.041) compared to G2. Conclusion: Among the determined experiment conditions, it was concluded that contact between silk sericin and pulp tissue showed improved inflammatory response throughout treatment and new cells proliferation. However, silk sericin adhibition in pure form did not show capability for induction of tertiary dentin formation.Keywords: Biocompatible Materials; Calcium Hydroxide; Dental Pulp Capping; Serici

Endothelial Dicer promotes atherosclerosis and vascular inflammation by miRNA-103-mediated suppression of KLF4

MicroRNAs regulate the maladaptation of endothelial cells (ECs) to naturally occurring disturbed blood flow at arterial bifurcations resulting in arterial inflammation and atherosclerosis in response to hyperlipidemic stress. Here, we show that reduced endothelial expression of the RNAse Dicer, which generates almost all mature miRNAs, decreases monocyte adhesion, endothelial C-X-C motif chemokine 1 (CXCL1) expression, atherosclerosis and the lesional macrophage content in apolipoprotein E knockout mice (Apoe(-/-)) after exposure to a high-fat diet. Endothelial Dicer deficiency reduces the expression of unstable miRNAs, such as miR-103, and promotes Kruppel-like factor 4 (KLF4)-dependent gene expression in murine atherosclerotic arteries. MiR-103 mediated suppression of KLF4 increases monocyte adhesion to ECs by enhancing nuclear factor-kappa B-dependent CXCL1 expression. Inhibiting the interaction between miR-103 and KLF4 reduces atherosclerosis, lesional macrophage accumulation and endothelial CXCL1 expression. Overall, our study suggests that Dicer promotes endothelial maladaptation and atherosclerosis in part by miR103-mediated suppression of KLF4