3,281 research outputs found
PropylÂammonium 4,4,4-trifluoro-1-(naphthalen-2-yl)butane-1,3-dionate
The title salt, C3H10N+·C14H8F3O2
−, constitutes the first organic crystal containing a residue of 4,4,4-trifluoro-1-(naphthalen-2-yl)butane-1,3-dione. The terminal –CF3 group is disordered over two locations [occupancy ratio = 0.830 (7):0.170 (7)]. Bond delocalization involving the two carbonyl groups and the α-carbon was observed. The crystal packing is mediated by several supraÂmolecular interÂactions, namely charged-assisted N—H⋯O hydrogen bonds, C—H⋯F and C—F⋯F short contacts and C—H⋯π interÂactions
Traumatic experiences in a lifetime: impact on the connection with others and the role of emotions
Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
Oscillation threshold of a clarinet model: a numerical continuation approach
This paper focuses on the oscillation threshold of single reed instruments.
Several characteristics such as blowing pressure at threshold, regime
selection, and playing frequency are known to change radically when taking into
account the reed dynamics and the flow induced by the reed motion. Previous
works have shown interesting tendencies, using analytical expressions with
simplified models. In the present study, a more elaborated physical model is
considered. The influence of several parameters, depending on the reed
properties, the design of the instrument or the control operated by the player,
are studied. Previous results on the influence of the reed resonance frequency
are confirmed. New results concerning the simultaneous influence of two model
parameters on oscillation threshold, regime selection and playing frequency are
presented and discussed. The authors use a numerical continuation approach.
Numerical continuation consists in following a given solution of a set of
equations when a parameter varies. Considering the instrument as a dynamical
system, the oscillation threshold problem is formulated as a path following of
Hopf bifurcations, generalizing the usual approach of the characteristic
equation, as used in previous works. The proposed numerical approach proves to
be useful for the study of musical instruments. It is complementary to
analytical analysis and direct time-domain or frequency-domain simulations
since it allows to derive information that is hardly reachable through
simulation, without the approximations needed for analytical approach
Response of an artificially blown clarinet to different blowing pressure profiles
Using an artificial mouth with an accurate pressure control, the onset of the
pressure oscillations inside the mouthpiece of a simplified clarinet is studied
experimentally. Two time profiles are used for the blowing pressure: in a first
set of experiments the pressure is increased at constant rates, then decreased
at the same rate. In a second set of experiments the pressure rises at a
constant rate and is then kept constant for an arbitrary period of time. In
both cases the experiments are repeated for different increase rates. Numerical
simulations using a simplified clarinet model blown with a constantly
increasing mouth pressure are compared to the oscillating pressure obtained
inside the mouthpiece. Both show that the beginning of the oscillations appears
at a higher pressure values than the theoretical static threshold pressure, a
manifestation of bifurcation delay. Experiments performed using an interrupted
increase in mouth pressure show that the beginning of the oscillation occurs
close to the stop in the increase of the pressure. Experimental results also
highlight that the speed of the onset transient of the sound is roughly the
same, independently of the duration of the increase phase of the blowing
pressure.Comment: 14 page
Impact of Delftia tsuruhatensis and Achromobacter xylosoxidans on Escherichia coli dual-species biofilms treated with antibiotic agents
Recently it was demonstrated that for urinary tract infections species with a lower or unproven pathogenic potential, such as Delftia tsuruhatensis and Achromobacter xylosoxidans, might interact with conventional pathogenic agents such as Escherichia coli. Here, single- and dual-species biofilms of these microorganisms were characterized in terms of microbial composition over time, the average fitness of E. coli, the spatial organization and the biofilm antimicrobial profile. The results revealed a positive impact of these species on the fitness of E. coli and a greater tolerance to the antibiotic agents. In dual-species biofilms exposed to antibiotics, E. coli was able to dominate the microbial consortia in spite of being the most sensitive strain. This is the first study demonstrating the protective effect of less common species over E. coli under adverse conditions imposed by the use of antibiotic agents.This work was financially supported by the FCT/MEC with
national funds and when applicable co-funded by FEDER in
the scope of the P2020 Partnership Agreement [Project UID/
EQU/00511/2013-LEPABE]; FEDER funds through the Operational
Programme for Competitiveness Factors – COMPETE,
O Novo Norte–North Portugal Regional Operational
Programme – ON2 and National Funds through Foundation
for Science and Technology – FCT [Project NORTE-07-0124-
FEDER-000025–RL2_ Environment&Health and Project
‘DNAmimics’ PIC/IC/82815/2007]; PhD fellowship [SFRH/
BD/82663/2011]; and postdoctoral fellowship [SFRH/
BPD/74480/2010]
Structural features and pro-inflammatory effects of water-soluble organic matter in inhalable fine urban air particles
The impact of inhalable fine particulate matter (PM2.5, aerodynamic diameter < 2.5 µm) on public health is of great concern worldwide. Knowledge on their harmful effects are mainly due to studies carried out with whole air particles, being the contribution of their different fractions largely unknown. Herein, a set of urban PM2.5 samples were collected during day and nighttime periods in Autumn and Spring, aiming to address the seasonal and day-night variability of water-soluble organic matter (WSOM) composition. In vitro analysis of oxidative and pro-inflammatory potential of WSOM samples was carried out in both acute (24 h) and chronic (3 weeks) exposure setups using Raw264.7 macrophages as cell model. Findings revealed that the structural composition of WSOM samples differs between seasons and in a day-night cycle. Cells exposure resulted in an increase in the transcription of the cytoprotective Hmox1 and pro-inflammatory genes Il1b and Nos2, leading to a moderate pro-inflammatory status. These macrophages showed an impaired capacity to subsequently respond to a strong pro-inflammatory stimulus such as bacterial lipopolysaccharide, which may implicate a compromised capacity to manage harmful pathogens. Further investigation on aerosol WSOM could help to constrain the mechanisms of WSOM-induced respiratory diseases and contribute to PM2.5 regulations.publishe
Enhanced bioproduction of poly-3-hydroxybutyrate from wheat straw lignocellulosic hydrolysates
Project: EC/FP7/246449 - New tailor-made PNB-based nanocomposites for high performance applications produced from environmentally friendly production routesNOTICE: this is the author’s version of a work that was accepted for publication in New Biotechnology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in New Biotechnology, [Vol. 31, Issue 1, (January 2014)] DOI 10.1016/j.nbt.2013.10.004"Polyhydroxyalkanoates (PHAs) are bioplastics that can replace conventional petroleum derived products in various applications. One of the major barriers for their widespread introduction in the market is the higher production costs when compared with their petrochemical counterparts. In this work, a process was successfully implemented with high productivity based on wheat straw, a cheap and readily available agricultural residue, as raw material. The strain Burkholderia sacchari DSM 17165 which is able to metabolize glucose, xylose and arabinose, the main sugars present in wheat straw hydrolysates (WSH), was used. Results in shake flask showed that B. sacchari cells accumulated ca 70 % g P(3HB)/g cell-dry-weight with a yield of polymer on sugars (YP/S) of 0.18 g/g when grown on a mixture of commercial C6 and C5 sugars (control), while these values reached ca 60 % g P(3HB)/g cell-dry-weight and 0.19 g/g, respectively, when WSHs were used as carbon source. In fed-batch cultures carried out in 2L stirred tank reactors on WSH, a maximum polymer concentration of 105 g/L was reached after 61 h of cultivation corresponding to an accumulation of 72% of CDW. Polymer yield and productivity were 0.22 g P(3HB)/g total sugar consumed and 1.6 g/L. h, respectively. The selected feeding strategy successfully overcame the carbon catabolite repression phenomenon observed in sugar mixtures containing hexoses and pentoses. This is the first work describing fed-batch cultivations aiming at PHA production using real lignocellulosic hydrolysates. Additionally, the P(3HB) volumetric productivities attained are, by far, the highest achieved ever on agricultural wastes hydrolysates."U
Control release of acyclovir nanocristals from electrospun nanofibers: comparison of two polymeric matrices
The objective of this study is to develop a novel system for cutaneous application of ACV that is capable of a controlled release of the drug overcoming the limitations of the conventional topical formulations.We are thankful to Labesfal Genericos, S.A. for kindly providing acyclovir. We also thank PARALAB for the SEM-EDS analysis and Dr. A. S. Azevedo for the X-ray analysis. This work was supported by
the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. Marlene Lúcio acknowledges the exploratory project funded by FCT with the reference IF/00498/2012.info:eu-repo/semantics/publishedVersio
The versatility of membrane-water partitioning in pharmacokinetic modelling
info:eu-repo/semantics/publishedVersio
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