Impact of composition and morphology on the optical properties of Si-NC/P3HT thin films processed from solution

Blends of Si nanocrystals (Si-NCs) and organic semiconductors are promising materials for new optical and electronic devices processed from solutions. Here, we study how the optical properties of composite films containing Si-NCs and the organic semiconductor poly(3-hexylthiophene) (P3HT) are influenced by the composition and morphology resulting from different solution-processing parameters and different solvents used dichlorobenzene vs. chloroform). The optical spectra of the hybrid films are described using a simple phenomenological model, with which we can discern the contribution of each material in the films to the optical properties. From this analysis, we obtain quantitative information about the composition and morphology of the hybrid nanostructured films, which otherwise would be obtained from more demanding microscopy and spectroscopy techniques. For the case of the Si-NC/P3HT blend, we find that in films deposited from dichlorobenzene solutions the Si-NCs contribute sizably to light absorption.This work was funded by FCT/I3N via the HybridSolar project, by the DFG via Teilprojekt B2 and by the European Union and the Ministry of Innovation, Science and Research of the German State of North Rhine-Westphalia in the framework of an Objective 2 Programme (European Regional Development Fund, ERDF). Funding is also acknowledged from the Portuguese Foundation for Science and Technology (FCT) through the Projects Nos. PTDC/FIS/112885/2009 and PEst-C/CTM/LA0025/2011 and via the Strategic Project LA 25:2011-2012

Pathophysiology of Blood–Brain Barrier Permeability Throughout the Different Stages of Ischemic Stroke and Its Implication on Hemorrhagic Transformation and Recovery

The blood-brain barrier (BBB) is a dynamic interface responsible for maintaining the central nervous system homeostasis. Its unique characteristics allow protecting the brain from unwanted compounds, but its impairment is involved in a vast number of pathological conditions. Disruption of the BBB and increase in its permeability are key in the development of several neurological diseases and have been extensively studied in stroke. Ischemic stroke is the most prevalent type of stroke and is characterized by a myriad of pathological events triggered by an arterial occlusion that can eventually lead to fatal outcomes such as hemorrhagic transformation (HT). BBB permeability seems to follow a multiphasic pattern throughout the different stroke stages that have been associated with distinct biological substrates. In the hyperacute stage, sudden hypoxia damages the BBB, leading to cytotoxic edema and increased permeability; in the acute stage, the neuroinflammatory response aggravates the BBB injury, leading to higher permeability and a consequent risk of HT that can be motivated by reperfusion therapy; in the subacute stage (1-3 weeks), repair mechanisms take place, especially neoangiogenesis. Immature vessels show leaky BBB, but this permeability has been associated with improved clinical recovery. In the chronic stage (>6 weeks), an increase of BBB restoration factors leads the barrier to start decreasing its permeability. Nonetheless, permeability will persist to some degree several weeks after injury. Understanding the mechanisms behind BBB dysregulation and HT pathophysiology could potentially help guide acute stroke care decisions and the development of new therapeutic targets; however, effective translation into clinical practice is still lacking. In this review, we will address the different pathological and physiological repair mechanisms involved in BBB permeability through the different stages of ischemic stroke and their role in the development of HT and stroke recovery.info:eu-repo/semantics/publishedVersio

Crystal Structure, Optical Second Harmonic Generation, Piezoelectricity and Pyroelectricity

Funding Information: This research was funded by Fundação para a Ciência e Tecnologia through FEDER (European Fund for Regional Development)-COMPETE-QREN-EU (ref. UID/FIS/04650/2013 and UID/FIS/04650/2019) and E-Field—“Electric-Field Engineered Lattice Distortions (E-FiELD) for optoelectronic devices”, ref. PTDC/NAN-MAT/0098/2020. C.S.B.G. acknowledges funding from Fundação para a Ciência e Tecnologia FCT/MCTES through projects UIDB/50006/2020, UIDP/50006/2020 and LA/P/0008/2020 of the Associate Laboratory for Green Chemistry—LAQV, UIDB/04378/2020, UIDP/04378/2020 and LA/P/0140/2020 of UCIBIO and Associate Laboratory i4HB, respectively. Funding Information: We acknowledge national funds (OE), through FCT − Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Publisher Copyright: © 2023 by the authors.A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, β = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to (Formula presented.), when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting.publishersversionpublishe

Assessment of potato peel and agro-forestry biochars supplementation on in vitro ruminal fermentation

UIDB/50006/2020 UIDB/04033/2020 grant ref. PDE/BDE/114434/2016 DL 57/2016 -Norma transitória.Background. The awareness of environmental and socio-economic impacts caused by greenhouse gas emissions from the livestock sector leverages the adoption of strategies to counteract it. Feed supplements can play an important role in the reduction of the main greenhouse gas produced by ruminants-methane (CH4). In this context, this study aims to assess the effect of two biochar sources and inclusion levels on rumen fermentation parameters in vitro. Methods. Two sources of biochar (agro-forestry residues, AFB, and potato peel, PPB) were added at two levels (5 and 10%, dry matter (DM) basis) to two basal substrates (haylage and corn silage) and incubated 24-h with rumen inocula to assess the effects on CH4 production and main rumen fermentation parameters in vitro. Results. AFB and PPB were obtained at different carbonization conditions resulting in different apparent surface areas, ash content, pH at the point of zero charge (pHpzc), and elemental analysis. Relative to control (0% biochar), biochar supplementation kept unaffected total gas production and yield (mL and mL/g DM, pD0.140 and pD0.240, respectively) and fermentation pH (p D 0.666), increased CH4 production and yield (mL and mL/g DM, respectively, pD0.001) and ammonia-N (NH3-N, pD0.040), and decreased total volatile fatty acids (VFA) production (p < 0.001) and H2 generated and consumed (p ≤ 0.001). Biochar sources and inclusion levels had no negative effect on most of the fermentation parameters and efficiency. Acetic.propionic acid ratio (pD0.048) and H2 consumed (pD0.019) were lower with AFB inclusion when compared to PPB. Biochar inclusion at 10% reduced H2 consumed (p < 0.001) and tended to reduce total gas production (pD0.055). Total VFA production (pD0.019), acetic acid proportion (pD0.011) and H2 generated (pD0.048) were the lowest with AFB supplemented at 10%, no differences being observed among the other treatments. The basal substrate affected most fermentation parameters independently of biochar source and level used. Discussion. Biochar supplementation increased NH3-N content, iso-butyric, iso-valeric and valeric acid proportions, and decreased VFA production suggesting a reduced energy supply for microbial growth, higher proteolysis and deamination of substrate N, and a decrease of NH3-N incorporation into microbial protein. No interaction was found between substrate and biochar source or level on any of the parameters measured. Although AFB and PPB had different textural and compositional characteristics, their effects on the rumen fermentation parameters were similar, the only observed effects being due to AFB included at 10%. Biochar supplementation promoted CH4 production regardless of the source and inclusion level, suggesting that there may be other effects beyond biomass and temperature of production of biochar, highlighting the need to consider other characteristics to better identify the mechanism by which biochar may influence CH4 production.publishersversionpublishe

Classificação dos níveis de degradação de pastagens em municípios paulistas por meio da combinação de bandas espectrais OLI/Landsat-8 e 9 e MSI/Sentinel-2.

RESUMO: As ferramentas de SIG estão em constante ascensão e desenvolvimento, fazendo com que as áreas de planejamento e mapeamento sejam amparadas com melhores análises e resoluções de cunho socioeconômico. O objetivo deste trabalho foi analisar, através de técnicas de sensoriamento remoto e informações baseadas em campo, a degradação da pastagem nos municípios de Brotas e São Carlos/SP. Os dados usados para o desenvolvimento do trabalho foram as imagens dos satélites OLI/Landsat-8-9 e MSI/Sentinel-2, de onde foram feitas classificações acerca da degradação da pastagem local, utilizando a técnica supervisionada. A partir disso, o algoritmo Random Forest foi usado com base nas combinações das bandas espectrais de cada satélite, juntamente com os índices de vegetação NDVI e SAVI. Posteriormente, com o cálculo do índice kappa, os melhores resultados de concordância com a coleta in situ puderam ser observados nas combinações de raster NDVI+B4+B5 e SAVI+B4+B8 para Landsat e Sentinel, respectivamente.CIIC 2023. Nº 23502

Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5, Brazil. LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical Mycology (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Treatment planning systems dosimetry auditing project in Portugal

BACKGROUND AND PURPOSE: The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this paper. MATERIAL AND METHODS: The audit methodology simulated all steps of external beam radiotherapy workflow, from image acquisition to treatment planning and dose delivery. A thorax CIRS phantom lend by IAEA was used in 8 planning test-cases for photon beams corresponding to 15 measuring points (33 point dose results, including individual fields in multi-field test cases and 5 sum results) in different phantom materials covering a set of typical clinical delivery techniques in 3D Conformal Radiotherapy. RESULTS: All 24 radiotherapy centers in Portugal have participated. 50 photon beams with energies 4-18 MV have been audited using 25 linear accelerators and 32 calculation algorithms. In general a very good consistency was observed for the same type of algorithm in all centres and for each beam quality. CONCLUSIONS: The overall results confirmed that the national status of TPS calculations and dose delivery for 3D conformal radiotherapy is generally acceptable with no major causes for concern. This project contributed to the strengthening of the cooperation between the centres and professionals, paving the way to further national collaborations

Characterization of complex networks: A survey of measurements

Each complex network (or class of networks) presents specific topological features which characterize its connectivity and highly influence the dynamics of processes executed on the network. The analysis, discrimination, and synthesis of complex networks therefore rely on the use of measurements capable of expressing the most relevant topological features. This article presents a survey of such measurements. It includes general considerations about complex network characterization, a brief review of the principal models, and the presentation of the main existing measurements. Important related issues covered in this work comprise the representation of the evolution of complex networks in terms of trajectories in several measurement spaces, the analysis of the correlations between some of the most traditional measurements, perturbation analysis, as well as the use of multivariate statistics for feature selection and network classification. Depending on the network and the analysis task one has in mind, a specific set of features may be chosen. It is hoped that the present survey will help the proper application and interpretation of measurements.Comment: A working manuscript with 78 pages, 32 figures. Suggestions of measurements for inclusion are welcomed by the author